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This book should be returned on or before the date last marked below.

A TREASURY
OF SCIENCE

Edited by

HARLOW SHAPLEY
SAMUEL RAPPORT and HELEN WRIGHT

With an Introduction by Dr. Shapley

Enlarged Edition

with a complete, new section
on atomic fission

HARPER & BROTHERS PUBLISHERS
NEW YORK AND LONDON

A Treasury of Science

COPYRIGHT, 1943, 1946 BY HARPER & BROTHERS
PRINTED IN THE UNITED STATES OF AMERICA

ALL RIGHTS IN THIS BOOK ARB RESERVED. NO PART OF THE BOOK
MAY BE REPRODUCED IN ANY MANNER WHATSOEVER WITHOUT
WRITTEN PERMISSION EXCEPT IN THE CASE OF BRIEF QUOTATIONS
EMBODIED IN CRITICAL ARTICLES AND REVIEWS. FOR INFORMATION
ADDRESS HARPER & BROTHERS

D-Y

TABLE OF CONTENTS

PREFACE ix

PREFACE TO THE NEW EDITION xi

Part One: INTRODUCTION
ON SHARING IN THE CONQUESTS OF SCIENCE by Harlow Shapley 3

Part Two: SCIENCE AND THE SCIENTIST

THE WONDER OF THE WORLD n

by Sir J. Arthur Thomson and Patricf^ Geddes

WE ARE ALL SCIENTISTS by T. H. Huxley 14

SCIENTISTS ARE LONELY MEN by Oliver La Forge 21

TURTLE EGGS FOR AGASSIZ by Dallas Lore Sharp 31

THE AIMS AND METHODS OF SCIENCE 42

by Roger Bacon, Albert Einstein, Sir Arthur Eddington,
Ivan Pavlov, and Raymond B. Fosdicf^

Part Three: THE PHYSICAL WORLD
A. THE HEAVENS

A THEORY THAT THE EARTH MOVES AROUND THE SUN 54

by Nicholas Copernicus

PROOF THAT THE EARTH MOVES by Galileo Galilei 58

THE ORDERLY UNIVERSE by Forest Ray Moulton . 62

Is THERE LIFE ON OTHER WORLDS? by Sir James Jeans 83

THE MILKY WAY AND BEYOND by Sir Arthur Eddington 89

B. THE EARTH

A YOUNG MAN LOOKING AT ROCKS by Hugh Miller 97

GEOLOGICAL CHANGE by Sir Archibald Geikf 103

EARTHQUAKES — WHAT ARE THEY? 114

by The Reverend James B. Macelwane, S.J.

LAST DAYS OF ST. PIERRE by Fairfax Downey 118

MAN, MAKER OF WILDERNESS by Paul B. Sears 126

WHAT MAKES THE WEATHER by Wolfgang Langeweische 132

vi TABLE OF CONTENTS

C. MATTER, ENERGY, PHYSICAL LAW

NEWTONIANA 147

DISCOVERIES by Sir Isaac Newton 150
MATHEMATICS, THE MIRROR OF CIVILIZATION by Lancelot Hogben 154

EXPERIMENTS AND IDEAS by Benjamin Franklin 168

1 EXPLORING THE ATOM by Sir James Jeans 175

TOURING THE ATOMIC WORLD by Henry Schacht 200

THE DISCOVERY OF RADIUM by Eve Curie 209

THE TAMING OF ENERGY by George Russell Harrison 218

SPACE, TIME AND EINSTEIN by Paul R. Hey I 228

THE FOUNDATIONS OF CHEMICAL INDUSTRY by Robert E. Rose 235

THE CHEMICAL REVOLUTION by Waldemar Kaempffert 248

JETS POWER FUTURE FLYING by Watson Davis 253

SCIENCE IN WAR AND AFTER by George Russell Harrison 257

Part Four: THE WORLD OF LIFE
A. THE RIDDLE OF LIFE

THE NATURE OF LIFE by W. J. V. Osterhout 273

THE CHARACTERISTICS OF ORGANISMS 280

by Sir /. Arthur Thomson and Patric\ Geddes

LEEUWENHOEK: FIRST OF THE MICROBE HUNTERS by Paul de Kruij 297

WHERE LIFE BEGINS by George W. Gray 307

B. THE SPECTACLE OF LIFE

•

ON BEING THE RIGHT SIZE by /. B. S. Haldane 321

PARASITISM AND DEGENERATION 326

by David Starr Jordan and Vernon Lyman Kellogg
FLOWERING EARTH by Donald Culross Peattie 337

A LOBSTER; OR, THE STUDY OF ZOOLOGY by T. H. Huxley 378

THE LIFE OF THE SIMPLEST ANIMALS

by David Starr Jordan and Vernon Lyman Kellogg 387

SECRETS OF THE OCEAN by William Beebe 395

THE WARRIOR ANTS by Caryl P. Hastens 406

THE VAMPIRE BAT 415

by Raymond L. Ditmars and Arthur M. Greenhall
ANCESTORS by Gustav Eckstein 426

TABLE OF CONTENTS vii
C. THE EVOLUTION OF LIFE

DARWINISMS 435

DARWIN AND "THE ORIGIN OF SPECIES" by Sir Arthur Keith 437

GREGOR MENDEL AND His WORK by Hugo lltis 446

THE COURTSHIP OF ANIMALS by Julian Huxley 453

MAGIC ACRES by Alfred Toombs 464

Part Five: THE WORLD OF MAN

A. FROM APE TO CIVILIZATION

THE EVIDENCE OF THE DESCENT OF MAN FROM SOME LOWER FORM 475

by Charles Darwin

THE UPSTART OF THE ANIMAL KINGDOM by Earnest A. Hooton 481

MISSING LINKS by John R. Baker 491

THE POPOL VUH 497

LESSONS IN LIVING FROM THE STONE AGE by Vilhjalmur Stefansson 502

RACIAL CHARACTERS OF THE BODY by Sir Arthur Keith 512

B. THE HUMAN MACHINE

You AND HEREDITY by Amram Scheinfeld 521

BIOGRAPHY OF THE UNBORN by Margaret Shea Gilbert 540

How THE HUMAN BODY Is STUDIED by Sir Arthur Keith 551

VARIATIONS ON A THEME BY DARWIN by Julian Huxley 557

C. THE CONQUEST OF DISEASE

THE HIPPOCRATIC OATH 568

HIPPOCRATES THE GREEK — THE END OF MAGIC by Logan Clendening 569

AN INQUIRY INTO THE CAUSES AND EFFECTS OF THE VARIOLAE VACCINAE 577

by Edward Jenner

THE HISTORY OF THE KINE Pox by Benjamin Water house 582

Louis PASTEUR AND THE CONQUEST OF RABIES by Rent Vallery-Radot 586

LEPROSY IN THE PHILIPPINES by Victor Heiser 604

WAR MEDICINE AND WAR SURGERY by George W. Gray 623

viii TABLE OF CONTENTS

D. MAN'S MIND

THINKING by James Harvey Robinson 638

IMAGINATION CREATRIX by John Livingston Lowes 650,

THE PSYCHOLOGY OF SIGMUND FREUD by A. A. Brill 655

BRAIN STORMS AND BRAIN WAVES by George W. Gray 673

Part Six: ATOMIC FISSION

WAR DEPARTMENT RELEASE ON NEW MEXICO TEST, JULY 16, 1945 689

ATOMIC ENERGY FOR MILITARY PURPOSES by Henry D. Smyth 695

NUCLEAR PHYSICS AND BIOLOGY by E. O. Lawrence - 727

ALMIGHTY ATOM by John J. O'Neill 741
THE IMPLICATIONS OF THE ATOMIC BOMB FOR INTERNATIONAL

RELATIONS by Jacob Viner 751

ATOMIC WEAPONS by J. R. Oppenheimer 760

ACKNOWLEDGMENTS 769

Preface

READER OF THIS BOOK MAY BE INTERESTED IN

the methods used in preparing it. We envisaged the audience as the
person without specialized knowledge; we accepted as our purpose to give
some realization of how the scientist works, of the body of knowledge
that has resulted and of the excitement of the scientist's search. One of
us has endeavored to convey some of that excitement in his Introduction,
On Sharing in the Conquests of Science.

We realized that a group of random selections, however good in them-
selves, would suggest little of the unity, the architectural quality of science.
We spent some months therefore in organizing the material before we
adopted a definite plan. The plan is evident from the titles of the major
Parts: Science and the Scientist, The Physical World, The World of Life
and The World of Man. The subdivisions carry through the plan in what
seems a logical sequence.

There followed a period of over a year during which several thousand
books and articles were examined in the light of this general scheme.
In making our selections we have tried to emphasize especially the status
and the contributions of modern science, to the end that the reader can
bring himself abreast of current progress. But in a few cases, we have
gone back the better part of a century to find the right discussion. We
have incorporated a number of biographical sketches of important scien-
tists, among them Pasteur, Madame Curie, Leeuwenhoek, in order to give
a glimpse of the personalities of scientific explorers. Also we have reached
generously into the past and selected classics of science, which not only
add flavor but also exhibit the work and workers who have done so much
to guide and inspire our civilization.

It has been found possible to avoid translations almost completely, since
the whole range of modern science has been explored assiduously by
English-writing people. Much assistance in the preparation of a volume
of this sort comes from the American standard magazines, and the semi-
popular scientific monthlies. They have provided for scientific writers an
incentive to summarize their work or the special field concerning which

x PREFACE

they write, in a fashion that is comprehensive, and comprehensible to the
layman.

We are also especially indebted to certain skillful scientific interpreters,
among them the English school of writers which includes the Huxleys,
Sir J. A. Thomson, Sir James Jeans, and J. B. S. Haldane. More than
once we have turned to their writings in preference to the scattered,
technical, fragmentary originals from which their synthetic pictures are
compounded.

Many important scientists are of course not represented in this collec-
tion, either because their writings have not been on the appropriate level,
or because in our judgment the reader can do better with another writer.
Limitations of space have also shortened and compressed many of the
selections. And since the volume is designed for the general reader and
not for the specialist, except when he is also a general reader, the addition
of references, technical footnotes and the similar apparatus of the serious
student are omitted.

We hope that the volume will justify itself in interest, and in instruc-
tional value, whether it is opened at random, or is methodically read from
beginning to end. For the reader who wishes to understand the full mean-
ing of any selection in relation to its context, we suggest a perusal of the
brief introductory notes at the beginnings of the main Parts.

As a general reference book this volume should have definite value.
For example, the attentive reading of Moulton, Jeans, and Eddington will
provide an authoritative picture of the fundamentals as well as the recent
advances of astronomy; and in short space the reader can obtain from
Langewiesche a fair understanding of modern weather prediction. Several
contributors make atomic structure or the past of man a well-rounded
story. And in a single essay subjects such as the Metagalaxy, earthquakes,
parasitism or Freudianism are each clearly summarized.

Nevertheless, the reader should realize that this work does not aim to
be encyclopedic in presentation. It is our hope that he will go further into
the vast stores of available writings to get specialized knowledge of any
branch of science that may interest him.

A contribution toward the integration of science is, as we have said,
one goal of this volume. We hope that it may be of particular value to
the scientific worker himself. No one works effectively in more than
one or two of the special fields. The average specialist is just as unin-
formed about science remote from his specialty as is the general reader.
A familiarity with other disciplines should not only be good entertain-
ment, but instructive as to techniques and attitudes. But of most impor-
tance, the scientific specialist, while reading abroad, is informing himself

PREFACE xi

on the inter-fields of science, or at least on the possibility and merit o£
inter-field study. If this volume can assist in however small a way in the
integration that seems essential to man's intelligent control of his own
fabrications, it will have attained the desired end.

Preface to the New Edition

NECESSITY OF A SECTION ON THE SCIENCE

-**• and world-disturbing consequences of the fission of uranium atoms, in
this second edition of our Treasury, can be attributed in considerable
part to several episodes, in modern scientific groping, that beautifully
illustrate the interlacing of the various sciences. We now commonly under-
stand that techniques devised by one science may carry over to another;
that results obtained in the biological realm may provide a key to mysteries
that shroud the inanimate.

But were we prepared to find that the study of paleozoic plant fossil
would combine with the theory of relativity to culminate in bombs that
frighten our civilization? Half a dozen fields of science have joined to
inaugurate the new age of atoms, rockets, radar and antibiotics. The
specialties contribute to astonishing generalizations and to surprising
end results. Perhaps our bringing of the varied classics of science into
this one large volume is justified on the grounds that science, thought
and life can be viewed as one integrated phenomenon.

Before the somewhat alarming release of atomic energy was accom-
plished by the nuclear physicists, there were underlying basic contribu-
tions by astronomers, paleontologists, chemists, botanists, geologists and
mathematicians. Some of the critical steps can be briefly cited: the
discovery and interpretation of radioactivity fifty years ago; the use of
the natural radioactivity of uranium and thorium to estimate the ages
of geological strata; the deduction that the life of half a billion years
ago required much the same quantity and quality of sunlight as we now
receive; the conclusion by astronomers that no other source than that
inside the atom could provide the required amount and duration of
solar energy; the growing realization that the energy in the atomic
nucleus, as liberated in the hot interiors of stars in accordance with the
principles of relativity, was the major power source of the universe; and,
finally, the application to uranium 235 of atom-cracking and power-re-
leasing radiation, with epochal consequences.

It has been a glorious build-up, involving the stars of galactic space and
the atoms of the microcosmos, and ending in the urgent need that the

xii PREFACE

social scientists and the practical citizens help to solve current problems,
both those of saving ourselves from the danger of our own ingenuity,
and those of capitalizing for the good of humanity the gains that are
now possible through the advances of science.

The two principal changes in the present edition are the considerable
extension of the selection from Jeans "Exploring the Atom" and the
supplement of several contributions relating to atomic energy. The reader
should not be misled by the emphasis on uranium and plutonium into
giving atomic energy exclusive credit for the atomic age. There are
many other contributors to the scientific revolution. Those popularly
known best are jet propulsion, radar, penicillin and sulfa drugs, rocketry,
blood derivatives and numerous developments in electronic magic.

But back of these modern evidences of human skill are the conquests
of generations of scientific workers who could think giant thoughts
and fabricate ingenious tools and theories without the rich accessories
now at hand. They laid the foundations on which we build foundations
for future builders. We hope that the Treasury of Science which recounts
many of these adventures of the past and present, will continue to
provide the reader with building material for his own constructions.

HARLOW SHAPLEY

PART ONE

INTRODUCTION

On Sharing in the Conquests of Science

HARLOW SHAPLEY

JT'S A WONDER I CAN STAND IT! TRAMPING FOR HOURS
JL through the damp woods back of Walden Pond with Henry Thoreau,
checking up on the food preferences of the marsh hawk, and the spread
of sumach and goldenrod in old abandoned clearings. It requires stamina
to match his stride as he plunges through swamps and philosophy,
through underbrush, poetry, and natural history; it takes agility of body
and mind if one does a full share of the day's measuring and speculation.

But no sooner have I left the Walden Woods than I am scrambling
up the fossil-rich Scottish cliffs with Hugh Miller, preparing the ground-
work of the immortal history of The Old Red Sandstone. With the
wonderment of pioneers we gaze at the petrified ripple-marks that
some shallow receding sea, in ancient times, has left as its fluted me-
morial— its monument built on the sand and of the sand, but nevertheless
enduring. We break open a stony ball — this Scottish stonemason and
I — a nodular mass of blue limestone, and expose beautiful traces o£
an extinct world of animals and plants; we find fossilized tree ferns,
giant growths from the Carboniferous Period of two hundred and fifty
million years ago — and forthwith we lose ourselves in conjecture.

And thea I am off on another high adventure, higher than the moon
this time; I am entering the study of the Frauenburg Cathedral to
help Nicholas Copernicus do calculations on the hypothetical motions
of the planets. He is, of course, deeply bemused with that rather queer
notion that it might be the Sun that stands still — not the Earth. Perhaps
he can demonstrate that the planets go around the Sun, each in its own
course. Fascinated, I peer over his shoulder at the archaic geometry,
watch his laborious penning of the great book, and listen to his
troubled murmuring about the inaccuracies of the measured coordinates
of Saturn. "There are, you know, two other big ones further out," I put
in; "and a system of m#ny moons around Jupiter, which makes it all
very clear and obvious." It must startle him no end to have me interrupt

3

4 INTRODUCTION

in such a confident way. But he does nothing about it. More planets? An
incredible idea! Difficulties enough in trying to explain the visible,
without complicating the complexities further by introducing invisible
planets. My assistance ignored, I experience, nevertheless, a carefree
exhilaration; for I have, as it were, matched my wits with the wisdom of
the greatest of revolutionaries, and come off not too badly!

Now that I am fully launched in this career of working with the
great explorers, and of cooperating in their attacks on the mysteries of
the universe, I undertake further heroic assignments. I labor in the
laboratories of the world; I maintain fatiguing vigils in the mountains
and on the sea, try dangerous experiments, and make strenuous expedi-
tions to Arctic shores and to torrid jungles — all without moving from
the deep fireside chair.

Benjamin Franklin has a tempting idea, and I am right there to lend
him a hand. We are having a lot of trouble in keeping that cantankerous
kite in the thunder-cloud, from which the electric fluid should flow to
charge and animate the house key. "Before long, Sir, we shall run
printing presses with this fluid, and light our houses, and talk around
the world"— but he does not put it in the Autobiography. I am clearly
a century ahead of my time!

Youthful Charles Darwin is in the Galapagos. The good brig Beagle
stands offshore. He has with him the collecting kit, the notebooks, and his
curiosity. He is making records of the slight variations among closely
similar species of plants and animals. He is pondering the origin of these
differences, and the origin of species, and the whole confounding business
of the origin of plants and animals. I sit facing him, on the rocks beside
the tide pool, admiring the penetration and grasp of this young dreamer.
The goal of his prolonged researches is a revolution in man's conception
of life; he is assembling the facts and thoughts, and in this work I am a
participant! Nothing could be more exciting. Also I have an advantage.
I know about Mendel and Mendelian laws, and genes and chromosomes.
I know that X-rays (unknown to Darwin), and other agents, can
produce mutations and suddenly create living forms that Nature has
not attained. This posterior knowledge of mine enhances the pleasure of
my collaboration with the great naturalist; and I need have no fear that
my information, or my ethereal presence, might bother him.

There is so much scientific work of this sort for me to do before some
tormenting duty draws me out of my strategic chair. The possibilities
are nearly endless. Like a benign gremlin, I sit on the brim of a test
tube in Marie Curie's laboratory and excitedly speculate with her on
that radioactive ingredient in the pitchblende; I help name it radium.

ON SHARING IN THE CONQUESTS OF SCIENCE 5

With Stefansson and the Eskimos I live for months on a scanty menu,
and worry with him about the evils of civilization. And when young
Evariste Galois, during his beautiful, brief, perturbed life in Paris, sits
down to devise sensationally new ideas and techniques in pure mathe-
matics, I am right there with applause and sympathy.

Whenever I pause to appreciate how simple it is for me to take an
active part in unravelling the home life of primitive man, or observing
the voracity of a vampire bat; how simple for me, in company with the
highest authorities, to reason on the theory of relativity or explore with
a cyclotron the insides of atoms, it is then that I call for additional
blessings on those artisans who invented printing. They have provided
me with guide lines to remote wonders — highly conductive threads that
lead me, with a velocity faster than that of light itself, into times long past
and into minds that biologically are long extinct. Through the simple
process of learning how to interpret symbols, such as those that make
this sentence, I can take part in most of the great triumphs of the human
intellect. Blessings and praises, laurel wreaths and myrtle, are due those
noble spirits who made writing and reading easily accessible, and thus
opened to us all the romance of scientific discovery.

Have you ever heard an ox warble? Probably not. Perhaps it goes
through its strange life-cycle silent to our gross ears. But I have seen ox
warbles, and through the medium of the printed page I have followed
their gory careers. The ox warbles to which I refer are, of course, not
bovine melodies, but certain flies that contribute to the discomfort of
cattle, to the impoverishment of man's property, and to the enrichment
of his knowledge of the insect world.1

It required a declaration of war on this entomological enemy, by
some of the great nations of the planet, in order to discover him com-
pletely and entrench mankind against his depredations. It took a century
of detective work on the part of entomologists to lay bare the ox warble's
secret life. Now that I have the story before me, I can go along with the
scientists and experience again their campaigns, their misadventures, and
their compensating discoveries. I can see how to connect a number
of separate phenomena that long were puzzling — those gay pasture flies
that look like little bumblebees; those rows of tiny white eggs on the
hairs above the hoofs of cattle; the growing larvae, guided mysteriously
by ancestral experience to wind their way for months through the flesh
of the legs and bodies of their unknowing hosts; the apparently inactive

1The full story of the ox warble is buried in various technical government reports. But
see a brief chapter on the subject in Insects — Man's Chief Competitors, by W. P. Flint and
C. L. Metcalf (Williams & Wilkins, 1932).

6 INTRODUCTION

worms in the cattle's throats; the large midwinter mounds, scattered
subcutaneously along the spines of the herd; and eventually those ruin-
ous holes in the leather, which have forced governments into aggressive
action — into defense-with-pursuit tactics for the protection of their eco-
nomic frontiers. It is all clear now. During the millennia of recent geolog-
ical periods a little fly has learned how to fatten its offspring on a fresh
beef diet, and prepare its huge grub for that critical moment when it
crawls out, through the hole it has made in the ox hide, and drops to
the earth for its metamorphosis — the change from a headless, legless,
eyeless, dark childhood to a maturity of wings and sunlight.

The curiosity the scientist strives to satisfy is thus sometimes im-
pelled by economics; more often by the pure desire to know. Our
black-on-white guiding threads, which you may call printed books, or
recorded history, not only transmit the stories of ancient and modern
inquisitiveness and the inquiries it has inspired, but they also report, to
the discerning recipient, the inevitability of practiced internationalism.
They transmit the message that all races of mankind are curious about
the universe, and that, when free and not too depressed by hunger, men
instinctively question and explore, analyze and catalogue. They have done
it in all ages, in all civilized countries. They work singly, in groups,
and increasingly in world-wide organizations. Science recognizes no
impossible national boundaries, and only temporary barriers of language.
It points the way to international cooperation.

To more than the art of printing, however, do we owe the successes
and pleasures of our vicarious adventures in science. We are also greatly
indebted to those who can write and will write in terms of our
limited comprehension. Not all the scientists have the facility. Some-
times the talk is too tough for us, or too curt. They have not the time
to be lucid on our level and within our vocabulary, or perhaps their
mental intensity has stunted the faculty of sympathetic explanation.
When such technical barriers shut us from the scientific workshop, it is
then we like to consult with a clear-spoken and understanding inter-
preter. We sit on the back porch of the laboratory, while he, as middle-
man, goes inside to the obscurities and mysteries, to return occasionally
with comprehensible reports. In listening to him we hear not only his
voice, but the overtones o£ the master he interprets. I like these men of
understanding who play Boswell to the specialist. They often have a
gift greater than that of the concentrated workers whom they soften
up for us. For they have breadth and perspective, which help us to
get at the essence of a problem more objectively than we could even if
we were fully equipped with the language and knowledge of the fact-

ON SHARING IN THE CONQUESTS OF SCIENCE 7

bent explorer and analyst. The scientific interpreters frequently enhance
our enjoyment in that they give us of themselves, as well as of the dis-
coverers whose exploits they recount. We are always grateful to them,
moreover, for having spared us labor and possibly discouragement.

Perhaps the greatest satisfaction in reading of scientific exploits and
participating, with active imagination, in the dull chores, the brave syn-
theses, the hard-won triumphs of scientific work, lies in the realization
that ours is not an unrepeatable experience. Tomorrow night we can
again go out among the distant stars. Again we can drop cautiously
below the ocean surface to observe the unbelievable forms that inhabit
those salty regions of high pressure and dim illumination. Again we can
assemble the myriad molecules into new combinations, weave them
into magic carpets that take us into strange lands of beneficent drugs
and of new fabrics and utensils destined to enrich the process of
everyday living. Again we can be biologist, geographer, astronomer,
engineer, or help the philosopher evaluate the nature and meaning of
natural laws.

We can return another day to these shores, and once more embark
for travels over ancient or modern seas in quest of half-known lands —
go forth as dauntless conquistadores, outfitted with the maps and gear
provided through the work of centuries of scientific adventures.

But we have done enough for this day. We have much to dream about.
Our appetites may have betrayed our ability to assimilate. The fare has
been irresistibly palatable. It is time to disconnect the magic threads;
time to wind up the spiral galaxies, roll up the Milky Way and lay it
aside until tomorrow.

1943

PART TWO

SCIENCE AND THE SCIENTIST

Synopsis

MANY STORIES OF JOURNEYS TO UNKNOWN LANDS HAVE
been written. Many tales of wonder have been told by the great writers
of the world. Yet it is common knowledge that the reality of modern science
is more wonderful than the imaginative world of a Poe, a Wells or a
Jules Verne. It is therefore unfortunate that the story has usually been told in
long words, written down in forbidding tomes. Like Agassiz's monumental
work on turtles, Contributions to the Natural History of the United States,
described by Dallas Lore Sharp in the following pages, they are "massive,
heavy, weathered as if dug from the rocks/' Yet there is amusement in
science, excitement, profound satisfaction. It is fitting that our first selection
should be an attempt to describe that feeling, The Wonder of the World
by Sir /. Arthur Thomson and Patrick Geddes.

Nor is science something esoteric, something mysterious and incompre-
hensible to the average person. We are all scientists, as T. H. Huxley shows
clearly, whether we are concerned with the properties of green apples or
with finding the burglar who stole our spoons. And we are led to our con-
clusions by "the same train of reasoning which a man of science pursues
when he is endeavoring to discover the origin and laws of the most occult
phenomena." One of the great scientists of the nineteenth century, as well
as its greatest scientific writer, Huxley is well qualified to instruct us.

The quality that sets the scientist apart is perhaps the persistence of his
curiosity about the world. That is what causes him to bury himself in his
laboratory or travel to a remote corner of the globe. Like Oliver La Farge,
in Scientists Are Lonely Men, he may spend months or even years on some
quest, seeming trivial yet destined perhaps to prove a clue to the origin of a
race. Or like Mr. Jenks of Middleboro, in Turtle Eggs for Agassiz, he may
spend countless hours beside a murky pond, waiting for a turtle to lay her

9

10 SCIENCE AND THE SCIENTIST

eggs. In both these tales there is much of the excitement, the emotional and
intellectual spirit of the scientific quest.

It is not possible in brief space to describe all the aspects of that quest.
But in The Aims and Methods of Science, a group of thinkers illuminate a
few of its many complexities. A passage from Roger Bacon shows why he is
considered one of the originators of scientific method. Albert Einstein asks
and answers the question, "Why does this magnificent applied science,
which saves work and makes life easier, bring us so little happiness?" Sir
Arthur Eddington shows that again and again the scientist must fly like
Icarus, before he finally reaches the sun. The passion of work and research is
Ivan Pavlov's theme. In a final selection, especially pertinent today as men
fight, Raymond B. Fosdick explains how the scientist cannot be bound by the
borders of sea or land, how no war can completely destroy his international
brotherhood.

The Wonder of the World

SIR J. ARTHUR THOMSON AND PATRICK GEDDES

From Life: Outlines of General Biology

ARISTOTLE, WHO WAS NOT UNACCUSTOMED TO
•4^. resolute thinking, tells us that throughout nature there is always
something of the wonderful — thaumaston. What precisely is this "won-
derful"? It cannot be merely the startling, as when we announce the fact
that if we could place in one long row all the hair-like vessels or capillaries
of the human body, which connect the ends of the arteries with the
beginnings of the veins, they would reach across the Atlantic. It would
be all the same to us if they reached only half-way across. Nor can the
wonderful be merely the puzzling, as when we are baffled by the "sailing"
of an albatross round and round our ship without any perceptible strokes
of its wings. For some of these minor riddles are being read every year,
without lessening, however, the fundamental wonderfulness of Nature.
Indeed, the much-abused word "wonderful" is properly applied to any fact
the knowledge of which greatly increases our appreciation of the signifi-
cance of the system of which we form a part. The truly wonderful maizes
all other things deeper and higher. Science is always dispelling mists —
the minor marvels; but it leaves us with intellectual blue sky, sublime
mountains, and deep sea. Their wonder appears — and remains.

There seems to be a rational basis for wonder in the abundance of power
in the world — the power that keeps our spinning earth together as it re-
volves round the sun, that keeps our solar system together as it journeys
through space at the rate of twelve miles a second towards a point in the
sky, close to the bright star Vega, called "the apex of the sun's way." At
the other extreme there is the power of a fierce little world within the com-
plex atom, whose imprisoned energies are set free to keep up the radiant
energies of sun and star. And between these extremes of the infinitely
great and the infinitely little are the powers of life — the power of winding
-up the clock almost as fast as it runs down, the power of a fish that has

11

12 SCIENCE AND THE SCIENTIST

better engines than those of a Mauretania, life's power of multiplying
itself, so that in a few hours an invisible microbe may become a fatal mil-
lion.

Another, also old-fashioned, basis for wonder is to be found in the im-
mensities. It takes light eight minutes to reach us from the sun, though it
travels at the maximum velocity — of about 186,300 miles per second. So
we see the nearest star by the light that left it four years ago, and Vega as
it was twenty-seven years ago, and most of the stars that we see without a
telescope as they were when Galileo Galilei studied them in the early years
of the seventeenth century. In any case it is plain that we are citizens of
no mean city.

A third basis for rational wonder is to be found in the intricacy and
manifoldness of things. We get a suggestion of endless resources in the
creation of individualities. Over two thousand years ago Aristotle knew
about five hundred different kinds of animals; and now the list of the
named and known includes twenty-five thousand different kinds of back-
boned animals, and a quarter of a million — some insist on a minimum of
half a million — backboneless animals, each itself and no other. For "all
flesh is not the same flesh, but there is one kind of flesh of men, another
flesh of beasts, another of fishes, and another of birds." The blood of a
horse is different from that of an ass, and one can often identify a bird
from a single feather or a fish from a few scales. One is not perhaps
greatly thrilled by the fact that the average man has twenty-five billions
of oxygen-capturing red blood corpuscles, which if spread out would oc-
cupy a surface of 3,300 square yards; but there is significance in the cal-
culation that he has in the cerebral cortex of his brain, the home of the
higher intellectual activities, some nine thousand millions of nerve cells,
that is to say, more than five times the present population of the globe —
surely more than the said brain as yet makes use of.

So it must be granted that we are fearfully and wonderfully made! Our
body is built up of millions of cells, yet there is a simplicity amid the
multitudinousness, for each cell has the same fundamental structure.
Within the colloid cell-substance there floats a kernel or nucleus, which
contains forty-seven (or in woman forty-eight) chromosomes, each with
a bead-like arrangement of smaller microsomes, and so on, and so on.
Similarly, while eighty-nine different elements have been discovered out
of the theoretically possible ninety-two, we know that they differ from
one another only in the number and distribution of the electrons and pro-
tons that make up their microcosmic planetary system. What artistry to
weave the gorgeously varied tapestry of the world out of two kinds of

THE WONDER OF THE WORLD 13

physical thread — besides, of course, Mind, which eventually searches into
the secret of the loom.

A fourth basis for rational wonder is in the orderliness of Nature, and
that is almost the same thing as saying its intelligibility. What implications
there are in the fact that man has been able to make a science of Nature!
Given three good observations of a comet, the astronomer can predict its
return to a night. It is not a phantasmagoria that we live in, it is a rational-
isable cosmos. The more science advances the more the fortuitous shrivels,
and the more the power of prophecy grows. Two astronomers foretold the
discovery of Neptune; the chemists have anticipated the discovery of new
elements; the biologist can not only count but portray his chickens before
they are hatched. The Order of Nature is the largest of all certainties; and
leading authorities in modern physics tell us that we cannot think of it as
emerging from the fortuitous. It is time that the phrase "a fortuitous con-
course of atoms" was buried. Even the aboriginal nebula was not that\ No
doubt there have been diseases and tragedies among men, cataclysms and
volcanic eruptions upon the earth, and so on — no one denies the shadows;
but even these disturbances are not disorderly; the larger fact is the ab-
sence of all caprice. To refer to the poet's famous line, no one any longer
supposes that gravitation can possibly cease when he goes by the avalanche.
Nor will a microbe's insurgence be influenced by the social importance of
the patient.

Corresponding to the intelligibility of Nature is the pervasiveness of
beauty — a fifth basis of rational wonder, appealing to the emotional side
of our personality. Surely Lotze was right, that it is of high value to look
upon beauty not as a stranger in the world, nor as a casual aspect of cer-
tain phenomena, but as "the fortunate revelation of that principle which
permeates all reality with its living activity."

A sixth basis of rational wonder is to be found in the essential character-
istics of living creatures. We need only add the caution that the marvel of
life is not to be taken at its face value; as Coleridge wisely said, the first
wonder is the child of ignorance; we must attend diligently to all that
biochemistry and biophysics can discount; we must try to understand all
that can be formulated in terms of colloids, and so on. Yet when all that
is said, there seem to be large residual phenomena whose emergence in
living creatures reveal a new depth in Nature. Life is an enduring, in-
surgent activity, growing, multiplying, developing, enregistering, varying,
and above all else evolving.

For this is the seventh wonder — Evolution. It is not merely that all
things flow; it is that life flows uphill. Amid the ceaseless flux there is
not only conservation, there is advancement. The changes are not those of

14 SCIENCE AND THE SCIENTIST

a kaleidoscope, but of "an onward advancing melody." As the unthink-
ably long ages passed the earth became the cradle and home of life; nobler
and finer kinds of living creatures appeared; there was a growing vic-
tory of life over things and of "mind" over "body"; until at last appeared
Man, who is Life's crowning wonder, since he has given to everything
else a higher and deeper significance. And while we must consider man
in the light of evolution, as most intellectual combatants admit, there is
the even more difficult task of envisaging evolution in the light of Man.
Finis coronat opus — a wise philosophical axiom; and yet the scientist must
qualify it by asking who can say Finis to Evolution.

1931

We Are All Scientists

T. H. HUXLEY

From Darwiniana

SCIENTIFIC INVESTIGATION IS NOT, AS MANY PEOPLE
seem to suppose, some kind of modern black art. You might easily
gather this impression from the manner in which many persons speak of
scientific inquiry, or talk about inductive and deductive philosophy, or the
principles of the "Baconian philosophy." I do protest that, of the vast
number of cants in this world, there are none, to my mind, so contempti-
ble as the pseudo-scientific cant which is talked about the "Baconian
philosophy."

To hear people talk about the great Chancellor — and a very great man
he certainly was, — you would think that it was he who had invented
science, and that there was no such thing as sound reasoning before the
time of Queen Elizabeth! Of course you say, that cannot possibly be true;
you perceive, OIL a moment's reflection, that such an idea is absurdly
wrong. . . .

WE ARE ALL SCIENTISTS 15

The method of scientific investigation is nothing but the expression
of the necessary mode of working of the human mind. It is simply
the mode at which all phenomena are reasoned about, rendered precise
and exact. There is no more difference, but there is just the same kind of
difference, between the mental operations of a man of science and those
of an ordinary person, as there is between the operations and methods of
a baker or of a butcher weighing out his goods in common scales, and the
operations of a chemist in performing a difficult and complex analysis by
means of his balance and finely-graduated weights. It is not that the action
of the scales in the one case, and the balance in the other, differ in the
principles of their construction or manner of working; but the beam of
one is set on an infinitely finer axis than the other, and of course turns by
the addition of a much smaller weight.

You will understand this better, perhaps, if I give you some familiar
example. You have all heard it repeated, I dare say, that men of science
work by means of induction and deduction, and that by the help of
these operations, they, in a sort of sense, wring from Nature certain
other things, which are called natural laws, and causes, and that out of
these, by some cunning skill of their own, they build up hypotheses
and theories. And it is imagined by many, that the operations of the
common mind can be by no means compared with these processes, and
that they have to be acquired by a sort of special apprenticeship to the
craft. To hear all these large words, you would think that the mind of
a man of science must be constituted differently from that of his fellow
men; but if you will not be frightened by terms, you will discover that
you are quite wrong, and that all these terrible apparatus are being
used by yourselves every day and every hour of your lives.

There is a well-known incident in one of Moliere's plays, where the
author makes the hero express unbounded delight on being told that he
had been talking prose during the whole of his life. In the same way,
I trust, that you will take comfort, and be delighted with yourselves, on
the discovery that you have been acting on the principles of inductive
and deductive philosophy during the same period. Probably there is not
one who has not in the course of the day had occasion to set in motion a
complex train of reasoning, of the very same kind, though differing of
course in degree, as that which a scientific man goes through in tracing
the causes of natural phenomena.

A very trivial circumstance will serve to exemplify this. Suppose you go
into a fruiterer's shop, wanting an apple, — you take up one, and, on biting
it, you find it is sour; you look at it, and see that it is hard and green. You
take up another one, and that too is hard, green, and sour. The shopman

16 SCIENCE AND THE SCIENTIST

offers you a third; but, before biting it, you examine it, and find that it
is hard and green, and you immediately say that you will not have it,
as it must be sour, like those that you have already tried.

Nothing can be more simple than that, you think; but if you will take
the trouble to analyse and trace out into its logical elements what has
been done by the mind, you will be greatly surprised. In the first place,
you have performed the operation of induction. You found that, in two
experiences, hardness and greenness in apples went together with sour-
ness. It was so in the first case, and it was confirmed by the second. True,
it is a very small basis, but still it is enough to make an induction from;
you generalise the facts, and you expect to find sourness in apples where
you get hardness and greenness. You found upon that a general law, that
all hard and green apples are sour; and that, so far as it goes, is a
perfect induction. Well, having got your natural law in this way, when
you are offered another apple which you find is hard and green, you say,
"All hard and green apples are sour; this apple is hard and green, there-
fore this apple is sour." That train of reasoning is what logicians call a
syllogism, and has all its various parts and terms — its major premiss, its
minor premiss, and its conclusion. And, by the help of further reason-
ing, which, if drawn out, would have to be exhibited in two or three other
syllogisms, you arrive at your final determination, "I will not have that
apple." So that, you see, you have, in the first place, established a law by
induction, and upon that you have founded a deduction, and reasoned out
the special conclusion of the particular case. Well now, suppose, having
got your law, that at some time afterwards, you are discussing the qualities
of apples with a friend: you will say to him, "It is a very curious thing, —
but I find that all hard and green apples are sour!" Your friend says to
you, "But how do you know that?" You at once reply, "Oh, because I have
tried them over and over again, and have always found them to be so."
Well, if we were talking science instead of common sense, we should call
that an experimental verification. And, if still opposed, you go further, and
say, "I have heard from the people in Somersetshire and Devonshire,
where a large number of apples are grown, that they have observed the
same thing. It is also found to be the case in Normandy, and in North
America. In short, I find it to be the universal experience of mankind
wherever attention has been directed to the subject." Whereupon, your
friend, unless he is a very unreasonable man, agrees with you, and is
convinced that you are quite right in the conclusion you have drawn.
He believes, although perhaps he does not know he believes it, that the
more extensive verifications are, — that the more frequently experiments
have been made, and results of the same kind arrived at, — that the more

WE ARE ALL SCIENTISTS 17

varied the conditions under which the same results are attained, the more
certain is the ultimate conclusion, and he disputes the question no further.
He sees that the experiment has been tried under all sorts of conditions,
as to time, place, and people, with the same result; and he says with you,
therefore, that the law you have laid down must be a good one, and he
must believe it.

In science we do the same thing; — the philosopher exercises precisely
the same faculties, though in a much more delicate manner. In scientific
inquiry it becomes a matter of duty to expose a supposed law to every
possible kind of verification, and to take care, moreover, that this is done
intentionally, and not left to a mere accident, as in the case of the apples.
And in science, as in common life, our confidence in a law is in exact pro-
portion to the absence of variation in the result of our experimental veri-
fications. For instance, if you let go your grasp of an article you may have
in your hand, it will immediately fall to the ground. That is a very com-
mon verification of one of the best established laws of nature — that of
gravitation. The method by which men of science establish the existence
of that law is exactly the same as that by which we have established the
trivial proposition about the sourness of hard and green apples. But we
believe it in such an extensive, thorough, and unhesitating manner because
the universal experience of mankind verifies it, and we can verify it our-
selves at any time; and that is the strongest possible foundation on which
any natural law can rest.

So much, then, by way of proof that the method of establishing laws in
science is exactly the same as that pursued in common life. Let us now
turn to another matter (though really it is but another phase of the same
question), and that is, the method by which, from the relations of certain
phenomena, we prove that some stand in the position of causes towards
the others.

I want to put the case clearly before you, and I will therefore show you
what I mean by another familiar example. I will suppose that one of you,
on coming down in the morning to the parlour of your house, finds that
a tea-pot and some spoons which had been left in the room on the previous
evening are gone, — the window is open, and you observe the mark of a
dirty hand on the window-frame, and perhaps, in addition to that, you
notice the impress of a hob-nailed shoe on the gravel outside. All these
phenomena have struck your attention instantly, and before two seconds
have passed you say, "Oh, somebody has broken open the window, entered
the room, and run off with the spoons and the tea-pot!" That speech is out
of your mouth in a moment. And you will probably add, "I know there
has; I am quite sure of it!" You mean to say exactly what you know;

18 SCIENCE AND THE SCIENTIST

but in reality you are giving expression to what is, in all essential partic-
ulars, an hypothesis. You do not \nous it at all; it is nothing but an
hypothesis rapidly framed in your own mind. And it is an hypothesis
founded on a long train of inductions and deductions.

What are those inductions and deductions, and how have you got at
this hypothesis? You have observed, in the first place, that the window is
open; but by a train of reasoning involving many inductions and deduc-
tions, you have probably arrived long before at the general law — and a
very good one it is — that windows do not open of themselves; and you
therefore conclude that something has opened the window. A second
general law that you have arrived at in the same way is, that tea-pots and
spoons do not go out of a window spontaneously, and you are satisfied
that, as they are not now where you left them, they have been removed.
In the third place, you look at the marks on the window-sill, and the shoe-
marks outside, and you say that in all previous experience the former
kind of mark has never been produced by anything else but the hand of
a human being; and the same experience shows that no other animal but
man at present wears shoes with hob-nails in them such as would produce
the marks in the gravel. I do not know, even if we could discover any of
those "missing links" that are talked about, that they would help us to
any other conclusion! At any rate the law which states our present experi-
ence is strong enough for my present purpose. You next reach the conclu-
sion, that as these kinds of marks have not been left by any other animals
than men, or are liable to be formed in any other way than by a man's
hand and shoe, the marks in question have been formed by a man in that
way. You have, further, a general law, founded on observation and
experience, and that, too, is, I am sorry to say, a very universal and unim-
peachable one, — that some men are thieves; and you assume at once from
all these premisses — and that is what constitutes your hypothesis — that the
man who made the marks outside and on the window-sill, opened the
window, got into the room, and stole your tea-pot and spoons. You have
now arrived at a vera causa; — you have assumed a cause which, it is plain,
is competent to produce all the phenomena you have observed. You can
explain all these phenomena only by the hypothesis of a thief. But that is
a hypothetical conclusion, of the justice of which you have no absolute
proof at all; it is only rendered highly probable by a series of inductive and
deductive reasonings.

I suppose your first action, assuming that you are a man of ordinary
common sense, and that you have established this hypothesis to your own
satisfaction, will very likely be to go for the police, and set them on the
track of the burglar, with the view to the recovery of your property. But

WE ARE ALL SCIENTISTS 19

just as you are starting with this object, some person comes in, and on
learning what you are about, says, "My good friend, you are going on a
great deal too fast. How do you know that the man who really made the
marks took the spoons? It might have been a monkey that took them, and
the man may have merely looked in afterwards." You would probably
reply, "Well, that is all very well, but you see it is contrary to all experience
of the way tea-pots and spoons are abstracted; so that, at any rate, your
hypothesis is less probable than mine." While you are talking the thing
over in this way, another friend arrives. And he might say, "Oh, my dear
sir, you are certainly going on a great deal too fast. You are most presump-
tuous. You admit that all these occurrences took place when you were
fast asleep, at a time when you could not possibly have known anything
about what was taking place. How do you know that the laws of Nature
are not suspended during the night? It may be that there has been some
kind of supernatural interference in this case." In point of fact, he declares
that your hypothesis is one of which you cannot at all demonstrate the
truth and that you are by no means sure that the laws of Nature are the
same when you are asleep as when you are awake.

Well, now, you cannot at the moment answer that kind of reasoning.
You feel that your worthy friend has you somewhat at a disadvantage.
You will feel perfectly convinced in your own mind, however, that you are
quite right, and you say to him, "My good friend, I can only be guided by
the natural probabilities of the case, and if you will be kind enough
to stand aside and permit me to pass, I will go and fetch the police."
Well, we will suppose that your journey is successful, and that by good
luck you meet with a policeman; that eventually the burglar is found with
your property on his person, and the marks correspond to his hand and to
his boots. Probably any jury would consider those facts a very good
experimental verification of your hypothesis, touching the cause of the
abnormal phenomena observed in your parlour, and would act accordingly.

Now, in this suppositious case, I have taken phenomena of a very com-
mon kind, in order that you might see what are the different steps in an
ordinary process of reasoning, if you will only take the trouble to analyse
it carefully. All the operations I have described, you will see, are involved
in the mind of any man of sense in leading him to a conclusion as to the
course he should take in order to make good a robbery and punish the
offender. I say that you are led, in that case, to your conclusion by exactly
the same train of reasoning as that which a man of science pursues when
he is endeavouring to discover the origin and laws of the most occult
phenomena. The process is, and always must be, the same; and precisely
the same mode of reasoning was employed by Newton and Laplace in

20 SCIENCE AND THE SCIENTIST

their endeavours to discover and define the causes of the movements of
the heavenly bodies, as you, with your own common sense, would
employ to detect a burglar. The only difference is, that the nature of the
inquiry being more abstruse, every step has to be most carefully watched,
so that there may not be a single crack or flaw in your hypothesis. A
flaw or crack in many of the hypotheses of daily life may be of little or
no moment as affecting the general correctness of the conclusions at which
we may arrive; but, in a scientific inquiry, a fallacy, great or small, is
always of importance, and is sure to be in the long run constantly produc-
tive of mischievous, if not fatal results.

Do not allow yourselves to be misled by the common notion that an
hypothesis is untrustworthy simply because it is an hypothesis. It is often
urged, in respect to some scientific conclusion, that, after all, it is only an
hypothesis. But what more have we to guide us in nine-tenths of the
most important affairs of daily life than hypotheses, and often very ill-
based ones? So that in science, where the evidence of an hypothesis is
subjected to the most rigid examination, we may rightly pursue the same
course. You may have hypotheses and hypotheses. A man may say, if he
likes, that the moon is made of green cheese: that is an hypothesis. But
another man, who has devoted a great deal of time and attention to the
subject, and availed himself of the most powerful telescopes and the
results of the observations of others, declares that in his opinion it is
probably composed of materials very similar to those of which our own
earth is made up: and that is also only an hypothesis. But I need not
tell you that there is an enormous difference in the value of the two
hypotheses. That one which is based on sound scientific knowledge is sure
to have a corresponding value; and that which is a mere hasty
random guess is likely to have but little value. Every great step in our
progress in discovering causes has been made in exactly the same way as
that which I have detailed to you. A person observing the occurrence of
certain facts and phenomena asks, naturally enough, what process, what
kind of operation known to occur in Nature applied to the particular case,
will unravel and explain the mystery? Hence you have the scientific
hypothesis; and its value will be proportionate to the care and completeness
with which its basis has been tested and verified. It is in these matters as in
the commonest affairs of practical life: the guess of the fool will be folly,
while the guess of the wise man will contain wisdom. In all cases, you see
that the value of the result depends on the patience and faithfulness with
which the investigator applies to his hypothesis every possible kind of
verification. . . .

1863

Scientists Are Lonely Men

OLIVER LA FARGE

IT IS NOT SO LONG AGO THAT, EVEN IN MY DILETTANTE
study of the science of ethnology, I corresponded with men in Ireland,
Sweden, Germany, France, and Yucatan, and had some discussion with
a Chinese. One by one these interchanges were cut off; in some countries
the concept of science is dead, and even in the free strongholds of Britain
and the Americas pure science is being — must be — set aside in favor of
what is immediately useful and urgently needed. It must hibernate now;
for a while all it means is likely to be forgotten.

It has never been well understood. Scientists have never been good at
explaining themselves and, frustrated by this, they tend to withdraw into
the esoteric, refer to the public as "laymen," and develop incomprehensible
vocabularies from which they draw a naive, secret-society feeling of
superiority.

What is the special nature of a scientist as distinguished from a soda-
jerker? Not just the externals such as his trick vocabulary, but the human
formation within the man? Most of what is written about him is rot; but
there is stuff there which a writer can get his teeth into, and it has its vivid,
direct relation to all that we are fighting for.

The inner nature of science within the scientist is both emotional and
intellectual. The emotional element must not be overlooked, for without
it there is no sound research on however odd and dull-seeming a subject.
As is true of all of us, an emotion shapes and forms the scientist's life;
at the same time an intellectual discipline molds his thinking, stamping
him with a character as marked as a seaman's although much less widely
understood.

To an outsider who does not know of this emotion, the scientist suggests
an ant, putting forth great efforts to lug one insignificant and apparently
unimportant grain of sand to be added to a pile, and much of the time his

21

22 SCIENCE AND THE SCIENTIST

struggle seems as pointless as an ant's. I can try to explain why he does it
and what the long-term purpose is behind it through an example from my
own work. Remember that in this I am not thinking of the rare, fortunate
geniuses like the Curies, Darwin, or Newton, who by their own talents
and the apex of accumulated thought at which they stood were knowingly
in pursuit of great, major discoveries. This is the average scientist, one
among thousands, obscure, unimportant, toilsome.

I have put in a good many months of hard work, which ought by usual
standards to have been dull but was not, on an investigation as yet un-
finished to prove that Kanhobal, spoken by certain Indians in Guatemala,
is not a dialect of Jacalteca, but that, on the contrary, Jacalteca is a dialect
of Kanhobal. Ridiculous, isn't it? Yet to me the matter is not only serious
but exciting. Why ?

There is an item of glory. There are half a dozen or so men now living
(some now, unfortunately, our enemies) who will pay me attention and
respect if I prove my thesis. A slightly larger number, less interested in the
details of my work, will give credit to La Farge for having added to the
linguistic map of Central America the name of a hitherto unnoted dialect.
But not until I have told a good deal more can I explain — as I shall pres-
ently— why the notice of so few individuals can constitute a valid glory.

There's the nature of the initial work. I have spent hours, deadly, difficult
hours, extracting lists of words, paradigms of verbs, constructions, idioms,
and the rest from native informants, often at night in over-ventilated huts
while my hands turned blue with cold. (Those mountains are far from
tropical.) An illiterate Indian tires quickly when giving linguistic informa-
tion. He is not accustomed to thinking of words in terms of other words;
his command of Spanish is so poor that again and again you labor over
misunderstandings; he does not think in our categories of words. Take
any schoolchild and ask him how you say, "I go." Then ask him in turn,
"Thou goest, he goes, we go." Even the most elementary schooling has
taught him, if only from the force of staring resentfully at the printed
page, to think in terms of the present tense of a single verb — that is, to
conjugate. He will give you, in Spanish for instance, "Me voy, te vas> se va>
nos vamos" &\\ in order. Try this on an illiterate Indian. He gives you his
equivalent of "I go," follows it perhaps with "thou goest," but the next
question reminds him of his son's departure that morning for Ixtatan, so
he answers "he sets out," and from that by another mental leap produces
"we are traveling." This presents the investigator with a magnificently
irregular verb. He starts checking back, and the Indian's mind being set
in the new channel, he now gets "I travel" instead of "I go."

There follows an exhausting process of inserting an alien concept into

SCIENTISTS ARE LONELY MEN 23

the mind of a man with whom you are communicating tenuously in a
language which you speak only pretty well and he quite badly.

Then of course you come to a verb which really is irregular and you
mistrust it. Both of you become tired, frustrated, upset. At the end of an
hour or so the Indian is worn out, his friendship for you has materially
decreased, and you yourself are glad to quit.

Hours and days of this, and it's not enough. I have put my finger upon
the village of Santa Eulalia and said, "Here is the true, the classic Kan-
hobal from which the other dialects diverge." Then I must sample the
others; there are at least eight villages which must yield me up fairly com-
plete word-lists and two from which my material should be as complete
as from Santa Eulalia. More hours and more days, long horseback trips
across the mountains to enter strange, suspicious settlements, sleep on the
dirt floor of the schoolhouse, and persuade the astonished yokelry that it
is a good idea, a delightful idea, that you should put "The Tongue1' into
writing. Bad food, a bout of malaria, and the early-morning horror of
seeing your beloved horse's neck running blood from vampire bats ("Oh,
but, yes, sefior, everyone knows that here are very troublesome the vam-
pire bats"), to get the raw material for proving that Jacalteca is a dialect
of Kanhobal instead of ...

You bring your hard-won data back to the States and you follow up with
a sort of detective-quest for obscure publications and old manuscripts
which may show a couple of words of the language as it was spoken a
few centuries ago, so that you can get a line on its evolution. With great
labor you unearth and read the very little that has been written bearing
upon this particular problem.

By now the sheer force of effort expended gives your enterprise value in
your own eyes. And you still have a year's work to put all your data in
shape, test your conclusions, and demonstrate your proof.

Yet the real emotional drive goes beyond all this. Suppose I complete my
work and prove, in fact, that Kanhobal as spoken in Santa Eulalia is a
language in its own right and the classic tongue from which Jacalteca has
diverged under alien influences, and that, further, I show just where the
gradations of speech in the intervening villages fit in. Dear God, what a
small, dull grain of sand!

But follow the matter a little farther. Jacalteca being relatively well-
known (I can, offhand, name four men who have given it some study),
from it it has been deduced that this whole group of dialects is most closely
related to the languages spoken south and east of these mountains. If my
theory is correct, the reverse is true — the group belongs to the Northern
Division of the Mayan Family. This fact, taken along with others regard-

24 SCIENCE AND THE SCIENTIST

ing physical appearance, ancient remains, and present culture, leads to a
new conclusion about the direction from which these tribes came into the
mountains: a fragment of the ancient history of what was once a great,
civilized people comes into view. So now my tiny contribution begins to
be of help to men working in other branches of anthropology than my
own, particularly to the archaeologists; it begins to help toward an even-
tual understanding of the whole picture in this area: the important ques-
tion of, not what these people are to-day, but how they got that way and
what we can learn from that about all human behavior including our
own.

Even carrying the line of research as far as this assumes that my results
have been exploited by men of greater attainments than I. Sticking to the
linguistic line, an error has been cleared away, an advance has been made
in our understanding of the layout and interrelationship of the many lan-
guages making up the Mayan Family. With this we come a step nearer to
working out the processes by which these languages became different from
one another and hence to determining the archaic, ancestral roots of the
whole group.

So far as we know at present, there are not less than eight completely
unrelated language families in America north of Panama. This is un-
reasonable: there are hardly that many families among all the peoples of
the Old World. Twenty years ago we recognized not eight, but forty.
Some day perhaps we shall cut the total to four. The understanding of the
Mayan process is a step toward that day; it is unlikely that Mayan will
remain an isolated way of speech unconnected with any other. We know
now that certain tribes in Wyoming speak languages akin to those of
others in Panama; we have charted the big masses and islands of that
group of tongues and from the chart begin to see the outlines of great
movements and crashing historical events in the dim past. If we should
similarly develop a relationship between Mayan and, let's say, the lan-
guages of the Mississippi Valley, again we should offer something provoc-
ative to the archaeologist, the historian, the student of mankind. Some
day we shall show an unquestionable kinship between some of these
families and certain languages of the Old World and with it cast a new
light on the dim subject of the peopling of the Americas, something to
guide our minds back past the Arctic to dark tribes moving blindly from
the high plateaus of Asia.

My petty detail has its place in a long project carried out by many men
which will serve not only the history of language but the broad scope of
history itself. It goes farther than that. The humble Pah-Utes of Nevada
speak a tongue related to that which the subtle Montezuma used, the one

SCIENTISTS ARE LONELY MEN 25

narrow in scope, evolved only to meet the needs of a primitive people, the
other sophisticated, a capable instrument for poetry, for an advanced gov-
ernmental system, and for philosophical speculation. Men's thoughts make
language and their languages make thought. When the matter of the
speech of mankind is fully known and laid side by side with all the other
knowledges, the philosophers, the men who stand at the gathering-together
point of science, will have the means to make man understand himself
at last.

Of course no scientist can be continuously aware of such remote possible
consequences of his labors; in fact the long goal is so remote that if he
kept his eyes on it he would become hopelessly discouraged over the half
inch of progress his own life's work will represent. But it was the vision
of this which first made him choose his curious career, and it is an emo-
tional sense of the great structure of scientific knowledge to which his
little grain will be added which drives him along.

ii

I spoke of the item of glory, the half dozen colleagues who will appre-
ciate one's work. To understand that one must first understand the isola-
tion of research, a factor which has profound effects upon the scientist's
psyche.

The most obvious statement of this is in the public attitude and folk-
literature about "professors." The titles and subjects of Ph.D. theses have
long been sources of exasperated humor among us; we are all familiar
with the writer's device which ascribes to a professorial character an in-
tense interest in some such matter as the development of the molars in
pre-Aurignacian man or the religious sanctions of the Levirate in north-
eastern Australia, the writer's intention being that the reader shall say "Oh
God!", smile slightly, and pigeonhole the character. But what do you sup-
pose is the effect of the quite natural public attitude behind these devices
upon the man who is excitedly interested in pre-Aurignacian molars and
who knows that this is a study of key value in tracing the evolution of
Homo sapiens?

Occasionally some line of research is taken up and made clear, even fasci-
nating, to the general public, as in Zinsser's Rats, Lice and History, or de
Kruif's rather Sunday-supplement writings. Usually, as in these cases, they
deal with medicine or some other line of work directly resulting in findings
of vital interest to the public. Then the ordinary man will consent to under-
stand, if not the steps of the research itself, at least its importance, will
grant the excitement, and honor the researcher. When we read Eve Curie's
great biography of her parents our approach to it is colored by our knowl-

26 SCIENCE AND THE SCIENTIST

edge, forty years later, of the importance of their discovery to every one
of us. It would have been quite possible at the time for a malicious or
merely ignorant writer to have presented that couple as archetypes of the
"professor," performing incomprehensible acts of self-immolation in
pursuit of an astronomically unimportant what's-it.

Diving to my own experience like a Stuka with a broken wing, I con-
tinue to take my examples from my rather shallow linguistic studies be-
cause, in its very nature, the kind of thing a linguist studies is so beauti-
fully calculated to arouse the "Oh God!" emotion.

It happened that at the suggestion of my letters I embarked upon an
ambitious, general comparative study of the whole Mayan Family. The
farther in I got the farther there was to go and the more absorbed I be-
came. Puzzle piled upon puzzle to be worked out and the solution used
for getting after the next one, the beginning of order in chaos, the glimpse
of understanding at the far end. Memory, reasoning faculties, realism, and
imagination were all on the stretch; I was discovering the full reach of
whatever mental powers I had. When I say that I became absorbed I
mean absorbed; the only way to do such research is to roll in it, become
soaked in it, live it, breathe it, have your system so thoroughly permeated
with it that at the half glimpse of a fugitive possibility everything you
have learned so far and everything you have been holding in suspension
is in order and ready to prove or disprove that point. You do not only
think about your subject while the documents are spread before you;
everyone knows that some of our best reasoning is done when the surface
of the mind is occupied with something else and the deep machinery of
the brain is free to work unhampered.

One day I was getting aboard a trolley car in New Orleans on my way
to Tulane University. As I stepped up I saw that if it were possible to
prove that a prefixed s- could change into a prefixed y- a whole series of
troublesome phenomena would fall into order. The transition must come
through u- and, thought I with a sudden lift of excitement, there may be
a breathing associated with u- and that may make the whole thing pos-
sible. As I paid the conductor I thought that the evidence I needed might
exist in Totonac and Tarascan, non-Mayan languages with which I was
not familiar. The possibilities were so tremendous that my heart pounded
and I was so preoccupied that I nearly went to sit in the Jim Crow sec-
tion. Speculation was useless until I could reach the University and dig
out the books, so after a while I calmed myself and settled to my morning
ration of Popeye, who was then a new discovery too. As a matter of fact,
the idea was no good, but the incident is a perfect example of the "profes-
sor mind."

SCIENTISTS ARE LONELY MEN 27

Of course, i£ as I stepped on to the car it had dawned upon me that the
reason my girl's behavior last evening had seemed odd was that she had
fallen for the Englishman we had met, the incident would not have seemed
so funny, although the nature of the absorption, subconscious thinking,
and realization would have been the same in both cases.

I lived for a month with the letter ^. If we have three words in Quiche,
one of the major Mayan languages, beginning with ^, in Kanhobal we
are likely to find that one of these begins with ch. Moving farther west
and north, in Tzeltal one is likely to begin with ^, one with ch, and the
one which began with ch in Kanhobal to begin with ts. In Hausteca, at
the extreme northwest, they begin with ^, ts, and plain s respectively. Why
don't they all change alike? Which is the original form? Which way do
these changes run, or from which point do they run both ways? Until
those questions can be answered we cannot even guess at the form of the
mother tongue from which these languages diverged, and at that point all
investigation halts. Are these J(s in Quiche pronounced even faintly
unlike? I noticed no difference between the two in Kanhobal, but then I
wasn't listening for it. I wished someone properly equipped would go and
listen to the Quiche Indians, and wondered if I could talk the University
into giving me money enough to do so.

This is enough to give some idea of the nature of my work, and its use-
lessness for general conversation. My colleagues at Tulane were archae-
ologists. Shortly after I got up steam they warned me frankly that I had
to stop trying to tell them about the variability of ^, the history of Puctun
tyy or any similar matter. If I produced any results that they could apply, I
could tell them about it; but apart from that I could keep my damned
sound-shifts and intransitive infixes to myself; I was driving them nuts.
My other friends on the faculty were a philosopher and two English pro-
fessors; I was pursuing two girls at the time but had not been drawn to
either because of intellectual interests in common; my closest friends were
two painters and a sculptor. The only person I could talk to was myself.

The cumulative effect of this non-communication was terrific. A strange,
mute work, a thing crying aloud for discussion, emotional expression, the
check and reassurance of another's point of view, turned in upon myself
to boil and fume, throwing upon me the responsibility of being my own
sole check, my own impersonal, external critic. When finally I came to
New York on vacation I went to see my Uncle John. He doesn't know
Indian languages but he is a student of linguistics, and I shall never forget
the relief, the reveling pleasure, of pouring my work out to him.

Thus at the vital point of his life-work the scientist is cut off from com-
munication with his fellow-men. Instead, he has the society of two, six, or

28 SCIENCE AND THE SCIENTIST

twenty men and women who are working in his specialty, with whom he
corresponds, whose letters he receives like a lover, with whom when he
meets them he wallows in an orgy of talk, in the keen pleasure of conclu-
sions and findings compared, matched, checked against one another — the
pure joy of being really understood.

The praise and understanding of those two or six become for him the
equivalent of public recognition. Around these few close colleagues is the
larger group of workers in the same general field. They do not share with
one in the steps of one's research, but they can read the results, tell in a
general way if they have been soundly reached, and profit by them. To
them McGarnigle "has shown" that there are traces of an ancient, doli-
chocephalic strain among the skeletal remains from Pusilha, which is
something they can use. Largely on the strength of his close colleagues'
judgment of him, the word gets round that McGarnigle is a sound man.
You can trust his work. He's the fellow you want to have analyze the
material if you turn up an interesting bunch of skulls. All told, including
men in allied fields who use his findings, some fifty scientists praise him;
before them he has achieved international reputation. He will receive hon-
ors. It is even remotely possible that he might get a raise in salary.

McGarnigle disinters himself from a sort of fortress made of boxes full
of skeletons in the cellar of Podunk University's Hall of Science, and
emerges into the light of day to attend a Congress. At the Congress he
delivers a paper entitled Additional Evidence of Dolichocephaly among
the Eighth Cycle Maya before the Section on Physical Anthropology. In
the audience are six archaeologists specializing in the Maya field, to whom
these findings have a special importance, and twelve physical anthropol-
ogists including Gruenwald of Eastern California, who is the only other
man working on Maya remains.

After McGarnigle's paper comes Gruenwald's turn. Three other physi-
cal anthropologists, engaged in the study of the Greenland Eskimo, the
Coastal Chinese, and the Pleistocene Man of Lake Mojave respectively,
come in. They slipped out for a quick one while McGarnigle was speak-
ing because his Maya work is not particularly useful to them and they can
read the paper later; what is coming next, with its important bearing on
method and theory, they would hate to miss.

Gruenwald is presenting a perfectly horrible algebraic formula and a
diagram beyond Rube Goldberg's wildest dream, showing A Formula for
Approximating the Original Indices of Artificially Deformed Crania.
(These titles are not mere parodies; they are entirely possible.) The archae-
ologists depart hastily to hear a paper in their own section on Indica-
tion^ of an Early Quinary System at Uaxactun. The formula is intensely

SCIENTISTS ARE LONELY MEN 29

exciting to McGarnigle because it was the custom of the ancient Mayas
to remodel the heads of their children into shapes which they (errone-
ously) deemed handsomer than nature's. He and Gruenwald have been
corresponding about this; at one point Gruenwald will speak of his col-
league's experience in testing the formula; he has been looking forward
to this moment for months.

After the day's sessions are over will come something else he has been
looking forward to. He and Gruenwald, who have not seen each other in
two years, go out and get drunk together. It is not that they never get
drunk at home, but that now when in their cups they can be uninhibited,
they can talk their own, private, treble-esoteric shop. It is an orgy of
release.

in

In the course of their drinking it is likely — if an archaeologist or two
from the area joins them it is certain — that the talk will veer from femoral
pilasters' and alveolar prognathism to personal experiences in remote sec-
tions of the Peten jungle. For in my science and a number of others there
is yet another frustration.

We go into the field and there we have interesting experiences. The
word "adventure" is taboo and "explore" is used very gingerly. But the
public mind has been so poisoned by the outpourings of bogus explorers
that it is laden with claptrap about big expeditions, dangers, hardships,
hostile tribes, the lighting of red flares around the camp to keep the sav-
ages at bay, and God knows what rot. (I can speak freely about this be-
cause my own expeditions have been so unambitious and in such easy
country that I don't come into the subject.) As a matter of fact it is gen-
erally true that for a scientist on an expedition to have an adventure is
evidence of a fault in his technique. He is sent out to gather information,
and he has no business getting into "a brush with the natives."

The red-flare, into-the-unknown, hardship-and-danger boys, who man-
age to find a tribe of pink-and-green Indians, a lost city, or the original,
handpainted descendants of the royal Incas every time they go out, usually
succeed in so riling the natives and local whites upon whom scientists
must depend if they are to live in the country as to make work in the
zones they contaminate difficult for years afterward. The business of their
adventures and discoveries is sickening. . . .

These men by training express themselves in factual, "extensional"
terms, which don't make for good adventure stories. They understand-
ably lean over backward to avoid sounding even remotely like the frauds,

30 SCIENCE AND THE SCIENTIST

the "explorers." And then what they have seen and done lacks validity to
them if it cannot be told in relation to the purpose and dominant emotion
which sent them there. McGarnigle went among the independent Indians
of Icaiche because he had heard of a skull kept in one of their temples
which, from a crude description, seemed to have certain important char-
acteristics. All his risks and his maneuverings v/ith those tough, explosive
Indians centered around the problem of gaining access to that skull. When
he tries to tell an attractive girl about his experiences he not only under-
states, but can't keep from stressing the significance of a skull with a
healed, clover-leaf trepan. The girl gladly leaves him for the nearest
broker. . . .

It is too bad both for the scientists and the public that they are so cut
off from each other. The world needs now not the mere knowledges of
science, but the way of thought and the discipline. It is the essence of
what Hitler has set out to destroy; against it he has waged total war within
his own domain. It is more than skepticism, the weighing of evidence
more even than the love of truth. It is the devotion of oneself to an end
which is far more important than the individual, the certainty that the
end is absolutely good, not only for oneself but for all mankind, and the
character to set personal advantage, comfort, and glory aside in the de-
voted effort to make even a little progress toward it.

Turtle Eggs for Agassiz

DALLAS LORE SHARP

YT IS ONE OF THE WONDERS OF THE WORLD THAT SO
-"* few books are written. With every human being a possible book, and
with many a human being capable of becoming more books than the
world could contain, is it not amazing that the books of men are so few?
And so stupid!

I took down, recently, from the shelves of a great public library, the
four volumes of Agassiz's Contributions to the Natural History of the
United States. I doubt if anybody but the charwoman, with her duster,
had touched those volumes for twenty-five years. They are an excessively
learned, a monumental, an epoch-making work, the fruit of vast and
heroic labors, with colored plates on stone, showing the turtles of the
United States, and their embryology. The work was published more than
half a century ago (by subscription) ; but it looked old beyond its years —
massive, heavy, weathered, as if dug from the rocks. It was difficult to feel
that Agassiz could have written it — could have built it, grown it, for the
laminated pile had required for its growth the patience and painstaking
care of a process of nature, as if it were a kind of printed coral reef. Agas-
siz do this? The big, human, magnetic man at work upon these pages of
capital letters, Roman figures, brackets, and parentheses in explanation of
the pages of diagrams and plates! I turned away with a sigh from the
weary learning, to read the preface.

When a great man writes a great book he usually flings a preface after
it, and thereby saves it, sometimes, from oblivion. Whether so or not, the
best things in most books are their prefaces. It was not, however, the qual-
ity of the preface to these great volumes that interested me, but rather the
wicked waste of durable book material that went to its making. Reading
down through the catalogue of human names and of thanks for help re-
ceived, I came to a sentence beginning: —

"In New England I have myself collected largely; but I have also re-

31

32 SCIENCE AND THE SCIENTIST

ceived valuable contributions from the late Rev. Zadoc Thompson of Bur-
lington . . . from Mr. D. Henry Thoreau of Concord . . . and from Mr.
J. W. P. Jenks of Middleboro." And then it hastens on with the thanks in
order to get to the turtles, as if turtles were the one and only thing of real
importance in all the world.

Turtles no doubt are important, extremely important, embryologically,
as part of our genealogical tree; but they are away down among the roots
of the tree as compared with the late Rev. Zadoc Thompson of Burling-
ton. I happen to know nothing about the Rev. Zadoc, but to me he looks
very interesting. Indeed any reverend gentleman of his name and day
who would catch turtles for Agassiz must have been interesting. And as
for Henry Thoreau, we know he was interesting. The rarest wood turtle
in the United States was not so rare a specimen as this gentleman of Wai-
den Woods and Concord. We are glad even for this line in the preface
about him; glad to know that he tried, in this untranscendental way, to
serve his day and generation. If Agassiz had only put a chapter in his
turtle book about it! But this is the material he wasted, this and more of
the same human sort, for the Mr. "Jenks of Middleboro" (at the end of the
quotation) was, years later, an old college professor of mine, who told me
some of the particulars of his turtle contributions, particulars which Agas-
siz should have found a place for in his big book. The preface says merely
that this gentleman sent turtles to Cambridge by the thousands — brief
and scanty recognition. For that is not the only thing this gentleman did.
On one occasion he sent, not turtles, but turtle eggs to Cambridge —
brought them, I should say; and all there is to show for it, so far as I
could discover, is a sectional drawing of a bit of the mesoblastic layer of
one of the eggs!

Of course, Agassiz wanted to make that mesoblastic drawing, or some
other equally important drawing, and had to have the fresh turtle egg to
draw it from. He had to have it, and he got it. A great man, when he
wants a certain turtle egg, at a certain time, always gets it, for he gets
someone else to get it. I am glad he got it. But what makes me sad and im-
patient is that he did not think it worth while to tell about the getting of
it, and so made merely a learned turtle book of what might have been an
exceedingly interesting human book.

It would seem, naturally, that there could be nothing unusual or inter-
esting about the getting of turtle eggs when you want them. Nothing at
all, if you should chance to want the eggs as you chance to find them. So
with anything else — good copper stock, for instance, if you should chance
to want it, and should chance to be along when they chance to be giving
it away. But if you want copper stock, say of C & H quality, when you

TURTLE EGGS FOR AGASSIZ 33

want it, and are bound to have it, then you must command more than a
college professor's salary. And likewise, precisely, when it is turtle eggs
that you are bound to have.

Agassiz wanted those turtle eggs when he wanted them — not a minute
over three hours from the minute they were laid. Yet even that does not
seem exacting, hardly more difficult than the getting of hen eggs only
three hours old. Just so, provided the professor could have had his private
turtle coop in Harvard Yard; and provided he could have made his turtles
lay. But turtles will not respond, like hens, to meat scraps and the warm
mash. The professor's problem was not to get from a mud turtle's nest in
the back yard to the table in the laboratory; but to get from the laboratory
in Cambridge to some pond when the turtles were laying, and back to
the laboratory within the limited time. And this, in the days of Darius
Green, might have called for nice and discriminating work — as it did.

Agassiz had been engaged for a long time upon his Contributions. He
had brought the great work nearly to a finish. It was, indeed, finished but
for one small yet very important bit of observation: he had carried the
turtle egg through every stage of its development with the single excep-
tion of one — the very earliest — that stage of first cleavages, when the cell
begins to segment, immediately upon its being laid. That beginning stage
had brought the Contributions to a halt. To get eggs that were fresh
enough to show the incubation at this period had been impossible.

There were several ways that Agassiz might have proceeded: he might
have got a leave of absence for the spring term, taken his laboratory to
some pond inhabited by turtles, and there camped until he should catch
the reptile digging out her nest. But there were difficulties in all of that —
as those who are college professors and naturalists know. As this was
quite out of the question, he did the easiest thing — asked Mr. "Jenks of
Middleboro" to get him the eggs. Mr. Jenks got them. Agassiz knew all
about his getting of them; and I say the strange and irritating thing is
that Agassiz did not think it worth while to tell us about it, a least in the
preface to his monumental work.

It was many years later that Mr. Jenks, then a gray-haired college pro-
fessor, told me how he got those eggs to Agassiz.

"I was principal of an academy, during my younger years," he began,
"and was busy one day with my classes, when a large man suddenly filled
the doorway of the room, smiled to the four corners of the room, and
called out with a big, quick voice that he was Professor Agassiz.

"Of course he was. I knew it, even before he had had time to shout it
to me across the room.

"Would I get him some turtle eggs? he called. Yes, I would. And would

34 SCIENCE AND THE SCIENTIST

I get them to Cambridge within three hours from the time they were laid?
Yes, I would. And I did. And it was worth the doing. But I did it only
once.

"When I promised Agassiz those eggs I knew where I was going to
get them. I had got turt le eggs there before — at a particular patch of sandy
shore along a pond, a few miles distant from the academy.

"Three hours was the limit. From the railroad station to Boston was
thirty-five miles; from tiie pond to the station was perhaps three or four
miles; from Boston to Cambridge we called about three miles. Forty miles
in round numbers! We figured it all out before he returned, and got the
trip down to two hours— record time: driving from the pond to the sta-
tion; from the station by express train to Boston; from Boston by cab to
Cambridge. This left an easy hour for accidents and delays.

"Cab and car and carriage we reckoned into our time-table; but what
we didn't figure on was the turtle." And he paused abruptly.

"Young man," he went on, his shaggy brows and spectacles hardly
hiding the twinkle in the eyes that were bent severely upon me, "young
man, when you go after turtle eggs, take into account the turtle. No! no!
That's bad advice. Youth never reckons on the turtle — and youth seldom
ought to. Only old age does that; and old age would never have got those
turtle eggs to Agassiz.

"It was in the early spring that Agassiz came to the academy, long
before there was any likelihood of the turtles laying. But I was eager for
the quest, and so fearful of failure that I started out to watch at the pond
fully two weeks ahead of the time that the turtles might be expected to
lay. I remember the date clearly: it was May 14.

"A little before dawn — along near three o'clock — I would drive over to
the pond, hitch my horse near by, settle myself quietly among some thick
cedars close to the sandy shore, and there I would wait, my kettle of sand
ready, my eye covering the whole sleeping pond. Here among the cedars I
would eat my breakfast, and then get back in good season to open the
academy for the morning session.

"And so the watch began.

"I soon came to know individually the dozen or more turtles that kept
to my side of the pond. Shortly after the cold mist would lift and melt
away they would stick up their heads through the quiet water; and as the
sun slanted down over the ragged rim of tree tops the slow things would
float into the warm, lighted spots, or crawl out and doze comfortably on
the hummocks and snags,

"What fragrant mornings those were! How fresh and new and un-
breathed! The pond odors, the woods odors, the odors of the ploughed

TURTLE EGGS FOR AGASSIZ 35

fields — of water lily, and wild grape, and the dew-laid soil! I can taste
them yet, and hear them yet — the still, large sounds of the waking day —
the pickerel breaking the quiet with his swirl; the kingfisher dropping
anchor; the stir of feet and wings among the trees. And then the thought
of the great book being held up for me! Those were rare mornings!

"But there began to be a good many of them, for the turtles showed no
desire to lay. They sprawled in the sun, and never one came out upon the
sand as if she intended to help on the great professor's book. The em-
bryology of her eggs was of small concern to her; her contribution to the
Natural History of the United States could wait.

"And it did wait. I began my watch on the fourteenth of May; June first
found me still among the cedars, still waiting, as I had waited every morn-
ing, Sundays and rainy days alike. June first saw a perfect morning, but
every turtle slid out upon her log, as if egg laying might be a matter strictly
of next year.

"I began to grow uneasy — not impatient yet, for a naturalist learns his
lesson of patience early, and for all his years; but I began to fear lest, by
some subtile sense, my presence might somehow be known to the crea-
tures; that they might have gone to some other place to lay, while I was
away at the schoolroom.

"I watched on to the end of the first week, on to the end of the second
week in June, seeing the mists rise and vanish every morning, and along
with them vanish, more and more, the poetry of my early morning vigil.
Poetry and rheumatism cannot long dwell together in the same clump of
cedars, and I had begun to feel the rheumatism. A month of morning
mists wrapping me around had at last soaked through to my bones. But
Agassiz was waiting, and the world was waiting, for those turtle eggs;
and I would wait. It was all I could do, for there is no use bringing a
china nest egg to a turtle; she is not open to any such delicate suggestion.

"Then came a mid-June Sunday morning, with dawn breaking a little
after three: a warm, wide-awake dawn, with the level mist lifted from the
level surface of the pond a full hour higher than I had seen it any morning
before.

"This was the day: I knew it. I have heard persons say that they can
hear the grass grow; that they know by some extra sense when danger is
nigh. That we have these extra senses I fully believe, and I believe they can
be sharpened by cultivation. For a month I had been watching, brooding
over this pond, and now I knew. I felt a stirring of the pulse of things
that the cold-hearted turtles could no more escape than could the clods
and I.

"Leaving my horse unhitched, as if he too understood, I slipped eagerly

36 SCIENCE AND THE SCIENTIST

into my covert for a look at the pond. As I did so, a large pickerel
ploughed a furrow out through the spatter-docks, and in his wake rose
the head of an enormous turtle. Swinging slowly around, the creature
headed straight for the shore, and without a pause scrambled out on the
sand.

"She was about the size of a big scoop shovel; but that was not what
excited me, so much as her manner, and the gait at which she moved; for
there was method in it, and fixed purpose. On she came, shuffling over the
sand toward the higher open fields, with a hurried, determined seesaw
that was taking her somewhere in particular, and that was bound to get
her there on time.

"I held my breath. Had she been a dinosaurian making Mesozoic foot-
prints, I could not have been more fearful. For footprints in the Mesozoic
mud, or in the sands of time, were as nothing to me when compared with
fresh turtle eggs in the sands of this pond.

"But over the strip of sand, without a stop, she paddled, and up a
narrow cow path into the high grass along a fence. Then up the narrow
cow path, on all fours, just like another turtle, I paddled, and into the
high wet grass along the fence.

"I kept well within sound of her, for she moved recklessly, leaving a
trail of flattened grass a foot and a half wide. I wanted to stand up, — and I
don't believe I could have turned her back with a rail, — but I was afraid
if she saw me that she might return indefinitely to the pond; so on I
went, flat to the ground, squeezing through the lower rails of the fence,
as if the field beyond were a melon patch. It was nothing of the kind, only
a wild, uncomfortable pasture, full of dewberry vines, and very dis-
couraging. They were excessively wet vines and briery. I pulled my coat
sleeves as far over my fists as I could get them, and, with the tin pail of
sand swinging from between my teeth to avoid noise, I stumped fiercely,
but silently, on after the turtle.

"She was laying her course, I thought, straight down the length of this
dreadful pasture, when, not far from the fence, she suddenly hove to,
warped herself short about, and came back, barely clearing me, at a clip
that was thrilling. I warped about, too, and in her wake bore down
across the corner of the pasture, across the powdery public road, and on to
a fence along a field of young corn.

"I was somewhat wet by this time, but not so wet as I had been before,
wallowing through the deep dry dust of the road. Hurrying up behind a
large tree by the fence, I peered down the corn rows and saw the turtle
stop, and begin to paw about in the loose soft soil. She was going to lay!

"I held on to the tree and watched, as she tried this place, and that place,

TURTLE EGGS FOR AGASSIZ 37

and the other place — the eternally feminine! But the place, evidently, was
hard to find. What could a female turtle do with a whole field of possible
nests to choose from? Then at last she found it, and, whirling about, she
backed quickly at it, and, tail first, began to bury herself before my staring
eyes.

"Those were not the supreme moments of my life; perhaps those
moments came later that day; but those certainly were among the slowest,
most dreadfully mixed of moments that I ever experienced. They were
hours long. There she was, her shell just showing, like some old hulk in
the sand alongshore. And how long would she stay there? And how
should I know if she had laid an egg?

"I could still wait. And so I waited, when, over the freshly awakened
fields, floated four mellow strokes from the distant town clock.

"Four o'clock! Why, there was no train until seven 1 No train for three
hours! The eggs would spoil! Then with a rush it came over me that this
was Sunday morning, and there was no regular seven o'clock train — none
till after nine.

"I think I should have fainted had not the turtle just then begun
crawling off. I was weak and dizzy; but there, there in the sand, were the
eggs! And Agassiz! And the great book! And I cleared the fence, and the
forty miles that lay between me and Cambridge, at a single jump. He
should have them, trains or no. Those eggs should go to Agassiz by seven
o'clock, if I had to gallop every mile of the way. Forty miles! Any horse
could cover it in three hours, if he had to; and, upsetting the astonished
turtle, I scooped out her round white eggs.

"On a bed of sand in the bottom of the pail I laid them, with what
care my trembling fingers allowed; filled in between them with more
sand; so with another layer to the rim; and, covering all smoothly with
more sand, I ran back for my horse.

"That horse knew, as well as I, that the turtle had laid, and that he
was to get those eggs to Agassiz. He turned out of that field into the road
on two wheels, a thing he had not done for twenty years, doubling me up
before the dashboard, the pail of eggs miraculously lodged between my
knees.

"I let him out. If only he could keep this pace all the way to Cambridge!
Or even halfway there; and I should have time to finish the trip on foot.
I shouted him on, holding to the dasher with one hand, the pail of eggs
with the other, not daring to get off my knees, though the bang on them,
as we pounded down the wood road, was terrific. But nothing must
happen to the eggs; they must not be jarred, or even turned over in the
sand before they come tc? Agassiz.

38 SCIENCE AND THE SCIENTIST

"In order to get out on the pike it was necessary to drive back away
from Boston toward the town. We had nearly covered the distance, and
were rounding a turn from the woods into the open fields, when, ahead
of me, at the station it seemed, I heard the quick sharp whistle of a loco-
motive.

"What did it mean? Then followed the puff, pufff puff of a starting
train. But what train? Which way going? And, jumping to my feet for a
longer view, I pulled into a side road that paralleled the track, and headed
hard for the station.

"We reeled along. The station was still out of sight, but from behind the
bushes that shut it from view rose the smoke of a moving engine. It was
perhaps a mile away, but we were approaching, head-on, and, topping a
little hill, I swept down upon a freight train, the black smoke pouring
from the stack, as the mighty creature pulled itself together for its swift
run down the rails.

"My horse was on the gallop, going with the track, and straight toward
the coming train. The sight of it almost maddened me — the bare thought
of it, on the road to Boston! On I went; on it came, a half— a quarter of a
mile between us, when suddenly my road shot out along an unfenced field
with only a level stretch of sod between me and the engine.

"With a pull that lifted the horse from his feet, I swung him into the
field and sent him straight as an arrow for the track. That train should
carry me and my eggs to Boston!

"The engineer pulled the rope. He saw me standing up in the rig, saw
my hat blow off, saw me wave my arms, saw the tin pail swing in my
teeth, and he jerked out a succession of sharp halts! But it was he who
should halt, not I; and on we went, the horse with a flounder landing the
carriage on top of the track.

"The train was already grinding to a stop; but before it was near a
stand-still I had backed off the track, jumped out, and, running down the
rails with the astonished engineers gaping at me, had swung aboard the
cab.

"They offered no resistance; they hadn't had time. Nor did they have
the disposition, for I looked strange, not to say dangerous. Hatless, dew-
soaked, smeared with yellow mud, and holding, as if it were a baby or a
bomb, a little tin pail of sand.

" 'Crazy,' the fireman muttered, looking to the engineer for his cue.

"I had been crazy, perhaps, but I was not crazy now.

"'Throw her wide open,' I commanded. 'Wide open! These are fresh
turtle eggs for Professor Agassiz of Cambridge. He must have them before
breakfast.'

TURTLE EGGS FOR AGASSIZ 39

"Then they knew I was crazy, and, evidently thinking it best to humor
me, threw the throttle wide open, and away we went.

"I kissed my hand to the horse, grazing unconcernedly in the open field,
and gave a smile to my crew. That was all I could give them, and hold
myself and the eggs together. But the smile was enough. And they smiled
through their smut at me, though one of them held fast to his shovel,
while the other kept his hand upon a big ugly wrench. Neither of them
spoke to me, but above the roar of the swaying engine I caught enough of
their broken talk to understand that they were driving under a full head of
steam, with the intention of handing me over to the Boston police, as
perhaps the easiest way of disposing of me.

"I was only afraid that they would try it at the next station. But that
station whizzed past without a bit of slack, and the next, and the next;
when it came over me that this was the through freight, which should
have passed in the night, and was making up lost time.

"Only the fear of the shovel and the wrench kept me from shaking
hands with both men at this discovery. But I beamed at them; and they at
me. I was enjoying it. The unwonted jar beneath my feet was wrinkling
my diaphragm with spasms of delight. And the fireman beamed at the
engineer, with a look that said, 'See the lunatic grin; he likes it!'

"He did like it. How the iron wheels sang to me as they took the rails!
How the rushing wind in my ears sang to me! From my stand on the fire-
man's side of the cab I could catch a glimpse of the track just ahead of the
engine, where the ties seemed to leap into the throat of the mile-devouring
monster. The joy of it! Of seeing space swallowed by the mile!

"I shifted the eggs from hand to hand and thought of my horse, of
Agassiz, of the great book, of my great luck, — luck, — luck, — until the
multitudinous tongues of the thundering train were all chiming 'luck!
luck! luck!' They knew! They understood! This beast of fire and tireless
wheels was doing its very best to get the eggs to Agassiz!

"We swung out past the Blue Hills, and yonder flashed the morning
sun from the towering dome of the State House. I might have leaped from
the cab and run the rest of the way on foot, had I not caught the eye of
the engineer watching me narrowly. I was not in Boston yet, nor in
Cambridge either. I was an escaped lunatic, who had held up a train, and
forced it to carry me to Boston.

"Perhaps I had overdone my lunacy business. Suppose these two men
should take it into their heads to turn me over to the police, whether I
would or no? I could never explain the case in time to get the eggs to
Agassiz. I looked at my watch. There were still a few minutes left, in
which I might explain to these men, who, all at once, had become my

40 SCIENCE AND THE SCIENTIST

captors. But it was too late. Nothing could avail against my actions, my
appearance, and my little pail of sand.

"I had not thought of my appearance before. Here I was, face and
clothes caked with yellow mud, my hair wild and matted, my hat gone,
and in my full-grown hands a tiny tin pail of sand, as if I had been
digging all night with a tiny tin shovel on the shore! And thus to appear
in the decent streets of Boston of a Sunday morning!

"I began to feel like a hunted criminal. The situation was serious, or
might be, and rather desperately funny at its best. I must in some way
have shown my new fears, for both men watched me more sharply.

"Suddenly, as we were nearing the outer freight yard, the train slowed
down and came to a stop. I was ready to jump, but I had no chance. They
had nothing to do, apparently, but to guard me. I looked at my watch
again. What time we had made! It was only six o'clock, with a whole hour
to get to Cambridge.

"But I didn't like this delay. Five minutes — ten — went by.

" 'Gentlemen,' I began, but was cut short by an express train coming
past. We were moving again, on — into a siding; on — on to the main
track; and on with a bump and a crash and a succession of crashes, run-
ning the length of the train; on at a turtle's pace, but on, when the fireman,
quickly jumping for the bell rope, left the way to the step free, and — the
chance had come!

"I never touched the step, but landed in the soft sand at the side of the
track, and made a line for the yard fence.

"There was no hue or cry. I glanced over my shoulder to see if they were
after me. Evidently their hands were full, and they didn't know I had
gone.

"But I had gone; and was ready to drop over the high board fence,
when it occurred to me that I might drop into a policeman's arms.
Hanging my pail in a splint on top of a post, I peered cautiously over — a
very wise thing to do before you jump a high board fence. There, crossing
the open square toward the station, was a big, burly fellow with a club —
looking for me.

"I flattened for a moment, when someone in the yard yelled at me. I
preferred the policeman, and, grabbing my pail, I slid over to the street.
The policeman moved on past the corner of the station out of sight. The
square was free, and yonder stood a cab!

"Time was flying now. Here was the last lap. The cabman saw me
coming, and squared away. I waved a paper dollar at him, but he only
stared the more. A dollar can cover a good deal, but I was too much for

TURTLE EGGS FOR AGASSIZ 41

one dollar. I pulled out another, thrust them both at him, and dodged
into the cab, calling, 'Cambridge!'

"He would have taken me straight to the police station had I not said,
'Harvard College. Professor Agassiz's house! I've got eggs for Agassiz';
and pushed another dollar up at him through the hole.

"It was nearly half past six.

" 'Let him go!' I ordered. "Here's another dollar if you make Agassiz's
house in twenty minutes. Let him out; never mind the police!'

"He evidently knew the police, or there were none around at that time
on a Sunday morning. We went down the sleeping streets as I had gone
down the wood roads from the pond two hours before, but with the rattle
and crash now of a fire brigade. Whirling a corner into Cambridge Street,
we took the bridge at a gallop, the driver shouting out something in
Hibernian to a pair of waving arms and a belt and brass buttons.

"Across the bridge with a rattle and jolt that put the eggs in jeopardy,
and on over the cobblestones, we went. Half standing, to lessen the jar, I
held the pail in one hand and held myself in the other, not daring to let
go even to look at my watch.

"But I was afraid to look at the watch. I was afraid to see how near to
seven o'clock it might be. The sweat was dropping from my nose, so close
was I running to the limit of my time.

"Suddenly there was a lurch, and I dived forward, ramming my head
into the front of the cab, coming up with a rebound that landed me
across the small of my back on the seat, and sent half of my pail of eggs
helter-skelter over the floor.

"We had stopped. Here was Agassiz's house; and without taking time
to pick up the scattered eggs I tumbled out, and pounded at the door.

"No one was astir in the house. But I would stir them. And I did. Right
in the midst of the racket the door opened. It was the maid.

"'Agassiz,' I gasped, 'I want Professor Agassiz, quick!' And I pushed
by her into the hall.

" 'Go 'way, sir. I'll call the police. Professor Agassiz is in bed. Go 'way,
sir!'

" 'Call him — Agassiz — instantly, or I'll call him myself.'

"But I didn't; for just then a door overhead was flung open, a great
white-robed figure appeared on the dim landing above, and a quick loud
voice called excitedly: —

" 'Let him in! Let him inl I know him. He has my turtle eggs!'

"And the apparition, slipperless, and clad in anything but an academic
gown, came sailing down the stairs,

42 SCIENCE AND THE SCIENTIST

"The maid fled. The great man, his arms extended, laid hold of me with
both hands, and, dragging me and my precious pail into his study, with a
swift, clean stroke laid open one of the eggs, as the watch in my trembling
hands ticked its way to seven — as if nothing unusual were happening to
the history of the world."

"You were in time, then?" I said.

"To the tick. There stands my copy of the great book. I am proud of the
humble part I had in it."

79/0

The Aims and Methods of Science

THE METHODS OF ACQUIRING KNOWLEDGE
ROGER BACON

ARE TWO METHODS IN WHICH WE ACQUIRE
-^ knowledge — argument and experiment. Argument allows us to
draw conclusions, and may cause us to admit the conclusion; but it
gives no proof, nor does it remove doubt, and cause the mind to rest
in the conscious possession of truth, unless the truth is discovered by
way of experience, e.g. if any man who had never seen fire were to
prove by satisfactory argument that fire burns and destroys things, the
hearer's mind would not rest satisfied, nor would he avoid fire; until by
putting his hand or some combustible thing into it, he proved by actual
experiment what the argument laid down; but after the experiment has
been made, his mind receives certainty and rests in the possession of
truth which could not be given by argument but only by experience.
And this is the case even in mathematics, where there is the strongest
demonstration. For let anyone have the clearest demonstration about an
equilateral triangle without experience of it, his mind will never lay

THE AIMS AND METHODS OF SCIENCE 43

hold of the problem until he has actually before him the intersecting
circles and the lines drawn from the point of section to the extremities
of a straight line.

12/4-1294

ADDRESS BEFORE THE STUDENT BODY
CALIFORNIA INSTITUTE OF TECHNOLOGY

ALBERT EIN.STEIN

Y DEAR YOUNG FRIENDS:

I am glad to see you before me, a flourishing band of young people
who have chosen applied science as a profession.

I could sing a hymn of praise with the refrain of the splendid progress
in applied science that we have already made, and the enormous further
progress that you will bring about. We are indeed in the era and also
in the native land of applied science.

But it lies far from my thought to speak in this way. Much more, I am
reminded in this connection of the young man who had married a not
very attractive wife and was asked whether or not he was happy. He
answered thus: "If I wished to speak the truth, then I would have to
lie."

So it is with me. Just consider a quite uncivilized Indian, whether his
experience is less rich and happy than that of the average civilized
man. I hardly think so. There lies a deep meaning in the fact that the
children of all civilized countries are so fond of playing "Indians."

Why does this magnificent applied science, which saves work and
makes life easier, bring us so little happiness? The simple answer
runs — because we have not yet learned to make a sensible use of it.

In war, it serves that we may poison and mutilate each other. In
peace it has made our lives hurried and uncertain. Instead of freeing us
in great measure from spiritually exhausting labor, it has made men into
slaves of machinery, who for the most part complete their monotonous
long day's work with disgust, and must continually tremble for their
poor rations.

You will be thinking that the old man sings an ugly song. I do it, how-
ever, with a good purpose, in order to point out a consequence.

44 SCIENCE AND THE SCIENTIST

It is not enough that you should understand about applied science
in order that your work may increase man's blessings. Concern for man
himself and his fate must always form the chief interest of all technical
endeavors, concern for the great unsolved problems of the organization
cf labor and the distribution of goods — in order that the creations of our
mind shall be a blessing and not a curse to mankind. Never forget this
in the midst of your diagrams and equations.

ICARUS IN SCIENCE
SIR ARTHUR EDDINGTON

From Stars and Atoms

IN ANCIENT DAYS TWO AVIATORS PROCURED TO
themselves wings. Daedalus flew safely through the middle air and
was duly honored on his landing. Icarus soared upwards to the sun till
the wax melted which bound his wings and his flight ended in fiasco.
In weighing their achievements, there is something to be said for
Icarus. The classical authorities tell us that he was only "doing a stunt,"
but I prefer to think of him as the man who brought to light a serious
constructional defect in the flying machines of his day. So, too, in science,
cautious Daedalus will apply his theories where he feels confident they
will safely go; but by his excesses of caution their hidden weaknesses
remain undiscovered. Icarus will strain his theories to the breaking
point till the weak points gape. For the mere adventure? Perhaps partly;
that is human nature. But if he is destined not yet to reach the sun and
solve finally the riddle of its constitution we may hope at least to
learn from his journey some hints to build a better machine.

7927

THE AIMS AND METHODS OF SCIENCE 45

BEQUEST TO THE ACADEMIC YOUTH OF HIS

COUNTRY

IVAN PAVLOV

SHALL I WISH FOR THE YOUNG STUDENTS OF

my country? First of all, sequence, consequence and again con-
sequence. In gaining knowledge you must accustom yourself to the
strictest sequence. You must be familiar with the very groundwork of
science before you try to climb the heights. Never start on the "next"
before you have mastered the "previous." Do not try to conceal the
shortcomings of your knowledge by guesses and hypotheses. Accustom
yourself to the roughest and simplest scientific tools. Perfect as the wing
of a bird may be, it will never enable the bird to fly if unsupported by
the air. Facts are the air of science. Without them the man of science
can never rise. Without them your theories are vain surmises. But while
you are studying, observing, experimenting, do not remain content with
the surface of things. Do not become a mere recorder of facts, but try
to penetrate the mystery of their origin. Seek obstinately for the laws that
govern them. And then—modesty. Never think you know all. Though
others may flatter you, retain the courage to say, "I am ignorant." Never
be proud. And lastly, science must be your passion. Remember that science
claims a man's whole life. Had he two lives they would not suuice.
Science demands an undivided allegiance from its followers. Li your
work and in your research there must always be passion.

THE SEARCH FOR UNITY
RAYMOND B. FOSDICK

THE BILL OF RIGHTS WILL OUTLAST MEIN KAMPF
just as the scientist's objective search for truth will outlive all the
regimented thinking of totalitarianism. Temporarily eclipsed, the proud

46 SCIENCE AND THE SCIENTIST

names of Paris, Strasbourg, Prague, Louvain, Warsaw, Leyden, as well
as Heidelberg and Leipsic and Berlin, will once again stand for the
quest for truth; once again will they be centers of candid and fearless
thinking—homes of the untrammeled and unafraid, where there is liberty
to learn, opportunity to teach and power to understand.

The task which faces all institutions concerned with the advance
of knowledge is not only to keep this faith alive but to make certain,
as far as they can, that the streams of culture and learning, wherever
they may be located or however feebly they may now flow, shall not
be blocked. . . .

... If we are to have a durable peace after the war, if out of the
Wreckage of the present, a new kind of cooperative life is to be built
on a global scale, the part that science and advancing knowledge will
play must not be overlooked. For although wars arid economic rivalries
may for longer or shorter periods isolate nations and split them up into
separate units, the process is never complete because the intellectual
life of the world, as far as science and learning are concerned, is definitely
internationalized, and whether we wish it or not an indelible pattern
of unity has been woven into the society of mankind.

There is not an area of activity in which this cannot be illustrated. An
American soldier, wounded on a battlefield in the Far East, owes his life
to the Japanese scientist, Kitasato, who isolated the bacillus of tetanus.
A Russian soldier, saved by a blood transfusion, is indebted to Land-
steiner, an Austrian. A German soldier is shielded from typhoid fever
with the help of a Russian, MetchnikofJ. A Dutch marine in the East
Indies is protected from malaria because of the experiments of an
Italian, Grassi; while a British aviator in North Africa escapes death
from surgical infection because a Frenchman, Pasteur, and a German,
Koch, elaborated a new technique.

In peace, as in war, we are all of us the beneficiaries of contributions
to knowledge made by every nation in the world. Our children are
guarded from diphtheria by what a Japanese and a German did, they
are protected from smallpox by an Englishman's work; they are saved
from rabies because of a Frenchman; they are cured of pellagra through
the researches of an Austrian. From birth to death, they are surrounded
by an invisible host — the spirits of men who never thought in terms of
flags or boundary lines and who never served a lesser loyalty than the
welfare of mankind. The best that every individual or group has
produced anywhere in the world has always been available to serve the
race of men, regardless of nation or color.

What is true of the medical sciences is true of the other sciences.

THE AIMS AND METHODS OF SCIENCE 47

Whether it is mathematics or chemistry, whether it is bridges or auto-
mobiles or a new device for making cotton cloth or a cyclotron for
studying atomic structure, ideas cannot be hedged in behind geographical
barriers. Thought cannot be nationalized. The fundamental unity of
civilization is the unity of its intellectual life.

There is a real sense, therefore, in which the things that divide us are
trivial as compared with the things that unite us. The foundations of a
cooperative world have already been laid. It is not as if we were starting
from the beginning. For at least three hundred years, the process has
been at work, until today the cornerstones of society are the common
interests that relate to the welfare of all men everywhere.

In brief, the age of distinct human societies, indifferent to the fate of
one another, has passed forever; and the great task that will confront
us after the war is to develop for the community of nations new areas and
techniques of cooperative action which will fit the facts of our twentieth
century interdependence. We need rallying points of unity, centers around
which men of different cultures and faiths can combine, defined fields of
need, or goals of effort, in which by pooling its brains and resources, the
human race can add to its own well-being. Only as we begin to build,
brick by brick, in these areas of common interest where cooperation is
possible and the results are of benefit to all, can we erect the ultimate
structure of a united society.

A score of inviting areas for this kind of cooperation deserve explo-
ration. Means must be found by which the potential abundance of the
world can be translated into a more equitable standard of living. Mini-
mum standards of food, clothing and shelter should be established. The
new science of nutrition, slowly coming to maturity, should be expanded
on a world-wide scale. The science of agriculture needs development,
not only in our own climate but particularly in the tropic and sub-
tropic zones. With all their brilliant achievements, the medical sciences
are in their infancy. Public health stands at the threshold of new
possibilities. Physics and chemistry have scarcely started their contri-
butions to the happiness and comfort of human living. Economics and
political science are only now beginning to tell us in more confident
tones how to make this world a home to live in instead of a place to
fight and freeze and starve in.

1941

PART THREE

THE PHYSICAL WORLD

Synopsis

A. THE HEAVENS

ON THE TWENTY-THIRD OF MAY, FOUR HUNDRED YEARS
ago, Nicholas Copernicus received on his death bed the first copy of his im-
mortal book, De Revolutionibus Orbium Coelestium (Concerning the Revo-
lutions of the Heavenly Bodies), in which he expressed his belief that the
earth moves around the sun. A few hours later he closed his eyes on a
medieval world that still believed in Ptolemy's geocentric universe.

Sixty-seven years later, in 1610, Galileo Galilei watched four small bodies
which appeared in the field of his telescope. Night after night he observed
them as they moved around the planet Jupiter. Here was a miniature solar
system similar to our own. Here was proof of the Copernican theory. Thus,
one of the greatest revolutions in the history of the human race took place.
Man was no longer the center of the world; he had assumed a subordinate
place in a larger universe.

In the following pages this story of Copernicus and Galileo is told in their
own words. As we read, some of the excitement and wonder which they
must have felt comes to us across the centuries.

Since that day, our knowledge of astronomy has greatly increased. We
know more about the planets; much more about the composition and even
the internal constitution of the stars; and we have discovered realms far be-
yond the range of Galileo's little telescope. This Orderly Universe extends
from OUT familiar satellite, the moon, to those exterior galaxies which are
visible only in the largest telescopes. To tell us about it, we chose Forest Ray
Moulton, who with T. C. Chamberlin is responsible for the modern theory
that the solar system was formed by the passage of a star near our own sun.
His description is an astronomical education in brief — a bird's-eye view ot
modern astronomy.

49

50 THE PHYSICAL WORLD

As man loolcs at the planets and shrinks in size before those distant gal-
axies, it is natural that he should ask Is There Life on Other Worlds? As
Sir James Jeans explains, science has its answer, based on facts of atmosphere,
temperature and mathematical ca/culation.

Life as we know it probably does not exist elsewhere in the solar system. It
may appear somewhere in our galaxy, or in some other galaxy outside the
Milky Way. We do not know, although we know much about these ex-
terior systems. In the field of external galaxies numerous recent develop-
ments have taken place. In The Milky Way and Beyond, Sir Arthur Edding-
ton, who is responsible for many of these developments, tells about them and
explains why he believes the universe is expanding. It is a fascinating hypoth-
esis, though there is disagreement among astronomers as to its correctness.
When the 2OO-inch telescope is finished, the problem may be solved.

B. THE EARTH

From outer space to A Young Man Looking at Rocks is a long jump to
more familiar ground. It is easier to contemplate the sculptured heart of a
fossil than the arms of a spiral nebula. Yet for that very reason, we are apt
to take the "commonest things" for granted. We forget that rocks, like
everything else, have a history. Old rocks hold the key to the age of the
earth; younger ones the clue to the origin of species. With Hugh Miller
we observe the history of the earth's crust spread before us, in massive blocks
of gneiss and hornblende and sedimentary beds of sandstone and shale. It is
charming autobiography from one of the classics of geology.

In the different types of rocks, Sir Archibald Geike can trace the story of
bygone ages. In the remarkable Geological Change, this famous nineteenth
century scientist describes the fundamentals of geology. He tells of the
rhythmic cycles caused by alternate erosion and uplifting of land. He tells of
the catastrophic changes which give rise to Earthquakes described by Father
Macelwane, or ferocious volcanic eruptions like that which doomed forty
thousand lives in St. Pierre, ironically saving the one man who was in /ail.

In the organic remains, the fossils, laid down in stratified rock, Geike
discerns forms now extinct — the ferns and conifers of which Peattie writes
in a later part; the scales of fishes found by Hugh Miller; the remains of
dinosaurs that once roamed the earth; even the fragments of prehistoric man,
the missing links about which you may read in Part Five.

Finally, like Paul B. Sears in Man, Maker of Wilderness, Geike watches
the effects of erosion on the land. Here is a clue to the decay of those civili-
zations which permit man to take everything from the earth, giving noth-
ing in return.

We have removed from Geological Change a section on the celebrated
nineteenth century controversy between the physicists and the geologists
about the age of the earth. The age set by the physicists, led by Lord Kelvin,
was far too short for the very slow and gradual changes the geologists

THE PHYSICAL WORLD 51

envisaged. That controversy was settled by the discovery of radium. It's dis-
integration furnished a source of energy the physicists had not taken into
their calculations. And its slow change into a unique type of lead within a
set period has furnished a valuable new geological clock. Examination of
radioactive substances in the oldest rocks now leads us to assign a period of
about 1,500,000,000 to 2,000,000,000 years as the age of the earth.

If we would understand the wind and the rain, we must know What
Makes the Weather. In aviation and agriculture and a thousand other activi-
ties, it is a problem of vital importance. In long range history, it may mean
climatic change that can alter the surface of a hemisphere. Here are the
modern theories about cold fronts and air masses. Here are the ideas which
help the weatherman become a successful prophet.

C. MATTER, ENERGY, PHYSICAL LAW

In 1642, when Galileo died an old and disillusioned man, he had already
learned a great deal about the mathematical meaning of motion. But he still
did not understand why the planets moved around the sun. He could not
know that in that same year a baby would be born who would create a world
conforming to both mathematical and physical law.

On Christmas Day, 1642, Isaac Newton was born in the village of Wools-
thorpe in Lincolnshire, a premature, frail baby, the posthumous son of a
yoeman farmer. Despite expectations to the contrary, he lived, and became the
greatest scientist in history. He was to discover the law of gravitation, the
laws of motion, the principles of optics, the composite nature of light, and
with Leibnitz to invent the calculus. He of course owed a great debt to
Galileo and to two other astronomers who lived in this same extraordinary
period: Tycho Brahe, who first recorded accurately the motions of the plan-
ets; and Johann Kepler whose laws of planetary motion showed how these
planets moved with relation to their central sun. On the foundations laid by
these three, Newton built a conception of the world and the forces that
guide it that was destined to hold undisputed place until the beginning of
the twentieth century, and even at that distant date to undergo but minor
modification.

Newtoniana tells us something of the man; while Discoveries gives us all
too brief glimpses of the work that made him what he was.

The Physical Laws of the world are not easy to comprehend. Mathematics,
physics and chemistry are so bound up with mysterious symbolism, not diffi-
cult in itself but unintelligible to those who have not learned its secret,
that words cannot give their full meaning. Yet meaning they do have, even
for the layman. Much of it is conveyed in the selections that follow.

First, let us consider mathematics, the foundation of physical law, the
indispensable tool of the scientist. It transforms indefinite thoughts into
specific theories. With its advance has come the advance of civilization. In

52 THE PHYSICAL WORLD

remote ages primitive man learned to count; later to measure; finally to cal-
culate. So we come to the modern world of science, where man must be a
"calculating animal" if he is to understand physical and even biological
science. Hogben tells something of the story in Mathematics, the Mirror of
Civilization.

From mathematics we turn to physics. But before we do so, let us consider
the Experiments and Ideas of that protean American Ben Franklin. He is
best known for his work with electricity, with kites and lightning rods. Few
remember his bifocal glasses, his discovery of the origin of northeast storms,
his extraordinary prophecy of aerial invasion.

In physics, we run squarely against one of the fundamental scientific prob-
lems of the century: what goes on inside the atom? In Exploring the Atom,
Sir James Jeans describes this strange world which all of us have heard about
yet few understand. He shows how our nineteenth century concept of the
atom as a sort of indestructible brick has been changed completely; he
makes the new picture of the atom really clear. And in doing so, he gives us
the basic knowledge which we must have to understand atomic fission and
the atomic bomb.

E. O. Lawrence, the California scientist who developed the world-famous
cyclotron, has become one of the leaders in research on atomic fission. Long
before our entrance into the war, his famous machine had "smashed the
atom/' In Touring the Atomic World, Henry Schacht gives a description of
his technique which the layman can understand. Not so long after this
article was written, wartime secrecy shrouded the work of Lawrence and
other nuclear physicists. The veil was lifted when a bomb exploded over
Hiroshima. It is interesting to note how much research went into the subject,
long before its military implications were thought of.

The first clue to the breaking up of the atomic nucleus was given by those
radioactive substances which disintegrate spontaneously. Jeans and Schacht
have told us something about them; and now we come to the work of that
extraordinary woman, Marie Curie, who kept house, brought up a family,
and discovered radium. The Discovery of Radium is a story which gains new
meaning when it is related to the course of modern physics.

It is impossible to think of the question of matter apart from the equally
fundamental one of energy. "Almost every problem of living turns out in the
last analysis to be a problem of the control of energy/' writes George Russell
Harrison of M. I. T. In The Taming of Energy, he tells us something of how
the various forms are interrelated. The question is complicated by Einstein,
who says that matter and energy are related according to mathematical law.
That relationship is deep water indeed, as is all relativity theory. Yet in Space,
Time and Einstein, Dr. Heyl, the man who weighed the earth, says interest-
ing things about relativity which are not too difficult for the informed lay-
man.

THE PHYSICAL WORLD 53

As physics and chemistry continue to advance, it becomes harder to decide
where one begins and the other ends. In the eighteenth century when
Lavoisier, "Father of Modern Chemistry/' died on the guillotine because the
French Revolution had "no need for scientists/' there was little connection.
In the nineteenth, when Mendeteef set up his periodic table, the gulf re-
mained. Basic work dealt with discovering and arranging the elements. In
the periodic table, Mendeteef arranged the elements according to their atomic
weights in somewhat the same way that the days of the month are arranged
on a calendar. When this was done, the elements in any vertical column
(the Sundays or Fridays) resembled one another in basic chemical properties.
As many elements had not been discovered, it was necessary to leave gaps in
the table. He prophesied that some day these gaps would be filled by ele-
ments which were then unknown, and this is exactly what has happened.

There is another aspect of chemistry which is perhaps of greater interest
to the lay reader — its application to everyday life. On chemical reactions
depend practically all industrial processes of the present day. On the re-
arrangement of atoms and molecules of substances which occur in nature,
depends the creation of the synthetics which are becoming an inseparable
part of our lives. One subject is discussed by the director of the Du Pont
laboratories in The Foundations of Chemical Industry; the other by the
Science Editor of the New York Times in The Chemical Revolution.

Finally comes the all-absorbing question of the war. Many weapons of
scientific warfare are held in greatest secrecy by various powers. But many
others can be discussed because they are known to all.

In Jets Power Future Flying, Watson Davis, the Director of Science
Service, the country's leading organization for the general dissemination of
scientific information, describes the various techniques whereby jet propul-
sion is revolutionizing aviation. In Science in War and After, Dr. Harrison
tells us about tanks that are tougher, aerial photography that sees farther,
naval guns that shoot straighter, and radio locators that see where human
eyes are useless.

A. THE HEAVENS

A Theory that the Earth Moves Around the Sun

NICHOLAS COPERNICUS

From Concerning the Revolutions of the Heavenly Bodies

THAT THE UNIVERSE IS SPHERICAL

THIRST OF ALL WE ASSERT THAT THE UNIVERSE IS

JL spherical; partly because this form, being a complete whole, needing
no joints, is the most perfect of all; partly because it constitutes the most
spacious form, which is thus best suited to contain and retain all things;
or also because all discrete parts of the world, I mean the sun, the moon
and the planets, appear as spheres; or because all things tend to assume
the spherical shape, a fact which appears in a drop of water and in other
fluid bodies when they seek of their own accord to limit themselves.
Therefore no one will doubt that this form is natural for the heavenly
bodies.

THAT THE EARTH IS LIKEWISE SPHERICAL

That the earth is likewise spherical is beyond doubt, because it presses
from all sides to its center. Although a perfect sphere is not immediately
recognized because of the great height of the mountains and the depres-
sion of the valleys, yet this in no wise invalidates the general spherical
form of the earth. This becomes clear in the following manner: To
people who travel from any place to the North, the north pole of the
daily revolution rises gradually, while the south pole sinks a like amount.
Most of the stars in the neighborhood of the Great Bear appear not to
set, and in the South some stars appear no longer to rise. Thus Italy
does not see Canopus, which is visible to the Egyptians. And Italy sees
the outermost star of the River, which is unknown to us of a colder zone.
On the other hand, to people who travel toward the South, these stars
rise higher in the heavens, while those stars which are higher to us

54

THE EARTH MOVES AROUND THE SUN 55

become lower. Therefore, it is plain that the earth is included between
the poles and is spherical. Let us add that the inhabitants of the East do
not see the solar and lunar eclipses that occur in the evening, and people
who live in the West do not see eclipses that occur in the morning, while
those living in between see the former later, and the latter earlier.

That even the water has the same shape is observed on ships, in that
the land which can not be seen from the ship can be spied from the tip
of the mast. And, conversely, when a light is put on the tip of the mast,
it appears to observers on land gradually to drop as the ship recedes until
the light disappears, seeming to sink in the water. It is clear that the
water, too, in accordance with its fluid nature, is drawn downwards, just
as is the earth, and its level at the shore is no higher than its convexity
allows. The land therefore projects everywhere only as far above the
ocean as the land accidentally happens to be higher. . . .

WHETHER THE EARTH HAS A CIRCULAR MOTION, AND CONCERNING
THE LOCATION OF THE EARTH

Since it has already been proved that the earth has the shape of a
sphere, I insist that we must investigate whether from its form can be
deduced a motion, and what place the earth occupies in the universe.
Without this knowledge no certain computation can be made for the
phenomena occurring in the heavens. To be sure, the great majority of
writers agree that the earth is at rest in the center of the universe, so that
they consider it unbelievable and even ridiculous to suppose the contrary.
Yet, when one weighs the matter carefully, he will see that this question
is not yet disposed of, and for that reason is by no means to be considered
unimportant. Every change of position which is observed is due either
to the motion of the observed object or of the observer, or to motions,
naturally in different directions, of both; for when the observed object
and the observer move in the same manner and in the same direction,
then no motion is observed. Now the earth is the place from which we
observe the revolution of the heavens and where it is displayed to our
eyes. Therefore, if the earth should possess any motion, the latter would
be noticeable in everything that is situated outside of it, but in the
opposite direction, just as if everything were traveling past the earth.
And of this nature is, above all, the daily revolution. For this motion
seems to embrace the whole world, in fact, everything that is outside of
the earth, with the single exception of the earth itself. But if one should
admit that the heavens possess none of this motion, but that the earth
rotates from west to east; and if one should consider this seriously with
respect to the seeming rising and setting of the sun, of the moon and

56 THE HEAVENS

the stars; then one would find that it is actually true. Since the heavens
which contain and retain all things are the common home of all things,
it is not at once comprehensible why a motion is not rather ascribed to
the thing contained than to the containing, to the located rather than to
the locating. This opinion was actually held by the Pythagoreans Heraklid
and Ekphantus and the Syracusean Nicetas (as told by Cicero), in that
they assumed the earth to be rotating in the center of the universe. They
were indeed of the opinion that the stars set due to the intervening of
the earth, and rose due to its receding. . . .

REFUTATION OF THE ARGUMENTS, AND THEIR INSUFFICIENCY

It is claimed that the earth is at rest in the center of the universe and
that this is undoubtedly true. But one who believes that the earth rotates
will also certainly be of the opinion that this motion is natural and not
violent. Whatever is in accordance with nature produces effects which
are the opposite of what happens through violence. Things upon wrhich
violence or an external force is exerted must become annihilated and
cannot long exist. But whatever happens in the course of nature remains
in good condition and in its best arrangement. Without cause, therefore,
Ptolemy feared that the earth and all earthly things if set in rotation
would be dissolved by the action of nature, for the functioning of nature
is something entirely different from artifice, or from that which could
be contrived by the human mind. But why did he not fear the same, and
indeed in much higher degree, for the universe, whose motion would
have to be as much more rapid as the heavens are larger than the earth?
Or have the heavens become infinite just because they have been removed
from the center by the inexpressible force of the motion; while otherwise,
if they were at rest, they would collapse? Certainly if this argument
were true the extent of the heavens would become infinite. For the more
they were driven aloft by the outward impulse of the motion, the more
rapid would the motion become because of the ever increasing circle
which it would have to describe in the space of 24 hours; and, con-
versely, if the motion increased, the immensity of the heavens would also
increase. Thus velocity would augment size into infinity, and size,
velocity. But according to the physical law that the infinite can neither
be traversed, nor can it for any reason have motion, the heavens would,
however, of necessity be at rest.

But it is said that outside of the heavens there is no body, nor place,
nor empty space, in fact, that nothing at all exists, and that, therefore,
there is no space in which the heavens could expand; then it is really
strange that something could be enclosed by nothing. If, however, the
heavens were infinite and were bounded only by their inner concavity,

THE EARTH MOVES AROUND THE SUN 57

then we have, perhaps, even better confirmation that there is nothing
outside of the heavens, because everything, whatever its size, is within
them; but then the heavens would remain motionless. The most impor-
tant argument, on which depends the proof of the finiteness of the
universe, is motion. Now, whether the world is finite or infinite, we will
leave to the quarrels of the natural philosophers; for us remains the
certainty that the earth, contained between poles, is bounded by a spher-
ical surface. Why should we hesitate to grant it a motion, natural and
corresponding to its form; rather than assume that the whole world,
whose boundary is not known and cannot be known, moves? And why
are we not willing to acknowledge that the appearance of a daily revolu-
tion belongs to the heavens, its actuality to the earth? The relation is
similar to that of which Virgil's /Eneas says: "We sail out of the harbor,
and the countries and cities recede." For when a ship is sailing along
quietly, everything which is outside of it will appear to those on board
to have a motion corresponding to the movement of the ship, and the
voyagers are of the erroneous opinion that they with all that they have
with them are at rest. This can without doubt also apply to the motion
of the earth, and it may appear as if the whole universe were revolving

CONCERNING THE CENTER OF THE UNIVERSE

. . . Since nothing stands in the way of the movability of the earth,
I believe we must now investigate whether it also has several motions,
so that it can be considered one of the planets. That it is not the center
of all the revolutions is proved by the irregular motions of the planets,
and their varying distances from the earth, which cannot be explained
as concentric circles with the earth at the center. Therefore, since there
are several central points, no one will without cause be uncertain
whether the center of the universe is the center of gravity of the earth
or some other central point. I, at least, am of the opinion that gravity
is nothing else than a natural force planted by the divine providence of
the Master of the World into its parts, by means of which they, assuming
a spherical shape, form a unity and a whole. And it is to be assumed that
the impulse is also inherent in the sun and the moon and the other
planets, and that by the operation of this force they remain in the spherical
shape in which they appear; while they, nevertheless, complete their
revolutions in diverse ways. If then the earth, too, possesses other motions
besides that around its center, then they must be of such a character as
to become apparent in many ways and in appropriate manners; and
among such possible effects we recognize the yearly revolution.

*543

Proof that the Earth Moves

GALILEO GALILEI

From The Sidereal Messenger

A BOUT TEN MONTHS AGO A REPORT REACHED MY
<L\. ears that a Dutchman had constructed a telescope, by the aid of
which visible objects, although at a great distance from the eye of the
observer, were seen distinctly as if near; and some proofs of its most
wonderful performances were reported, which some gave credence to,
but others contradicted. A few days after, I received confirmation of the
report in a letter written from Paris by a noble Frenchman, Jaques
Badovere, which finally determined me to give myself up first to inquire
into the principle of the telescope, and then to consider the means by
which I might compass the invention of a similar instrument, which
after a little while I succeeded in doing, through deep study of the theory
of Refraction; and I prepared a tube, at first of lead, in the ends of
which I fitted two glass lenses, both plane on one side, but on the other
side one spherically convex, and the other concave. Then bringing my
eye to the concave lens I saw objects satisfactorily large and near, for
they appeared one-third of the distance off. and nine times larger than
when they are seen with the natural eye alone. I shortly afterwards con-
structed another telescope with more nicety, which magnified objects
more than sixty times. At length, by sparing neither labour nor expense,
I succeeded in constructing for myself an instrument so superior that
objects seen through it appear magnified nearly a thousand times, and
more than thirty times nearer than if viewed by the natural powers of
sight alone.

FIRST TELESCOPIC OBSERVATIONS

It would be altogether a waste of time to enumerate the number and
importance of the benefits which this instrument may be expected to

58

PROOF THAT THE EARTH MOVES 59

confer, when used by land or sea. But without paying attention to its
use for terrestrial objects, I betook myself to observations of the heavenly
bodies; and first of all, I viewed the Moon as near as if it was scarcely
two semidiameters of the Earth distant. After the Moon, I frequently
observed other heavenly bodies, both fixed stars and planets, with
incredible delight. . . .

DISCOVERY OF JUPITER'S SATELLITES

There remains the matter, which seems to me to deserve to be con-
sidered the most important in this work, namely, that I should disclose
and publish to the world the occasion of discovering and observing four
planets, never seen from the very beginning of the world up to our own
times, their positions, and the observations made during the last two
months about their movements and their changes* of magnitude. . . .

On the yth day of January in the present year, 1610, in the first hour
of the following night, when I was viewing the constellations of the
heavens through a telescope, the planet Jupiter presented itself to my
view, and as I had prepared for myself a very excellent instrument, I
noticed a circumstance which I had never been able to notice before,
owing to want of power in my other telescope, namely,, that three little
stars, small but very bright, were near the planet; and although I
believed them to belong to the number of the fixed stars, yet they made
me somewhat wonder, because they seemed to be arranged exactly in a
straight line, parallel to the ecliptic, and to be brighter than the rest
of the stars, equal to them in magnitude. The position of them with
reference to one another and to Jupiter was as follows:

Ori. * * O * Occ.

On the east side there were two stars, and a single one towards the west.
The star which was furthest towards the east, and the western star,
appeared rather larger than the third.

I scarcely troubled at all about the distance between them and Jupiter,
for, as I have already said, at first I believed them to be fixed stars; but
when on January 8th, led by some fatality, I turned again to look at
the same part of the heavens, I found a very different state of things,
for there were three little stars all west of Jupiter, and nearer together
than on the previous night, and they were separated from one another
by equal intervals, as the accompanying figure shows.

60 THE HEAVENS

Ori. O * * * Occ.

At this point, although I had not turned my thoughts at all upon the
approximation of the stars to one another, yet my surprise began to be
excited, how Jupiter could one day be found to the east of all the afore-
said fixed stars when the day before it had been west of two of them;
and forthwith I became afraid lest the planet might have moved differ-
ently from the calculation of astronomers, and so had passed those stars
by its own proper motion. I, therefore, waited for the next night with the
most intense longing, but I was disappointed of my hope, for the sky
was covered with clouds in every direction.

But on January loth the stars appeared in the following position with
regard to Jupiter, the third, as I thought, being

Ori. * * O Occ.

hidden by the planet. They were situated just as before, exactly in the
same straight line with Jupiter, and along the Zodiac.

When I had seen these phenomena, as I knew that corresponding
changes of position could not by any means belong to Jupiter, and as,
moreover, I perceived that the stars which I saw had always been the
same, for there were no others either in front or behind, within a great
distance, along the Zodiac — at length, changing from doubt into surprise,
I discovered that the interchange of position which I saw belonged not to
Jupiter, but to the stars to which my attention had been drawn, and I
thought therefore that they ought to be observed henceforward with
more attention and precision.

Accordingly, on January nth I saw an arrangement of the follow-
ing kind:

Ori. * * O Occ.

namely, only two stars to the east of Jupiter, the nearer of which was dis-
tant from Jupiter three times as far as from the star further to the east;
and the star furthest to the east was nearly twice as large as the other
one; whereas on the previous night they had appeared nearly of equal
magnitude. I, therefore, concluded, and decided unhesitatingly, that there
are three stars in the heavens moving about Jupiter, as Venus and
Mercury round the Sun; which at length was established as clear as
daylight by numerous other subsequent observations. These observations

PROOF THAT THE EARTH MOVES 61

also established that there are not only three, but four, erratic sidereal
bodies performing their revolutions round Jupiter. . . .

These are my observations upon the four Medicean planets, recently
discovered for the first time by me; and although it is not yet permitted
me to deduce by calculation from these observations the orbits of these
bodies, yet I may be allowed to make some statements, based upon them,
well worthy of attention.

ORBITS AND PERIODS OF JUPITER's SATELLITES

And, in the first place, since they are sometimes behind, sometimes
before Jupiter, at like distances, and withdraw from this planet towards
the east and towards the west only within very narrow limits of
divergence, and since they accompany this planet alike when its motion
is retrograde and direct, it can be a matter of doubt to no one that they
perform their revolutions about this planet while at the same time they
all accomplish together orbits of twelve years' length about the centre
of the world. Moreover, they revolve in unequal circles, which is evi-
dently the conclusion to be drawn from the fact that I have never been
permitted to see two satellites in conjunction when their distance from
Jupiter was great, ^whereas near Jupiter two, three, and sometimes all
four, have been found closely packed together. Moreover, it may be
detected that the revolutions of the satellites which describe the smallest
circles round Jupiter are the most rapid, for the satellites nearest to
Jupiter are often to be seen in the east, when the day before they have
appeared in the west, and contrariwise. Also, the satellite moving in the
greatest orbit seems to me, after carefully weighing the occasions of its
returning to positions previously noticed, to have a periodic time of half
a month. Besides, we have a notable and splendid argument to remove
the scruples of those who can tolerate the revolution of the planets
round the Sun in the Copernican system, yet are so disturbed by the
motion of one Moon about the Earth, while both accomplish an orbit
of a year's length about the Sun, that they consider that this theory of
the universe must be upset as impossible; for now we have not one
planet only revolving about another, while both traverse a vast orbit
about the Sun, but our sense of sight presents to us four satellites circling
about Jupiter, like the Moon about the Earth, while the whole system
travels over a mighty orbit about the Sun in the space of twelve years.

1610

The Orderly Universe

FOREST RAY MOULTON

iN THE CLEAR VAULT OF THE HEAVENS MANY
shining objects are seen — the sun by day, the moon and numerous
stars at night. In comparison with the enormous earth beneath our feet,
they all appear to be insignificant bodies. Indeed, the sun and the moon
are often hidden from our view by a passing cloud, while the stars are
only scintillating points of light. Not only do the heavenly bodies appear
to be relatively small, but men in all ages almost down to our own have
believed that they are small. The general conception of the relative impor-
tance of the various bodies in the cosmos is illustrated by the story of
creation in Genesis. According to this account, after the earth had been
created, "God made two great lights" in the sky above, "the greater light
to rule the day, and the lesser light to rule the night." And then, almost
as if it were an afterthought, "he made the stars also."

Often in the history of science it has been found that "things are not
what they seem." It has been so in the history of astronomy to a marked
degree. Perhaps in no other field of exploration have the differences
between appearances and realities been so great. On the one hand, this
apparently limitless planet on which we dwell has been reduced relatively
to a particle of dust floating in the immensity of space; while, on the
other hand, "the greater light," hanging like a lamp in the sky, has been
expanded to a flaming mass of gas a million times greater in volume than
the earth. More remarkable still, the tiny twinkling stars, instead of being
fireflies of the heavens, are in reality other suns, many greater than our
own, whose glories are dimmed only by their enormous distances from
us; and the soft circle of light which we know as the Milky Way has
been found to be a vast cosmic system of twenty thousand million stars.

Amazing are the differences between what the heavenly bodies appear
to be and what they actually are. Equally amazing are the differences
between the intervals of time within the range of direct human experience

62

THE ORDERLY UNIVERSE 63

and the enormous periods covered by the cosmic processes. Historians
speak of the civilizations which long ago flourished in the valleys of the
Nile and the Euphrates as being ancient, and from the standpoint of
human history they are ancient. Yet all the written records which arche-
ologists have recovered from the buried ruins of long-forgotten cities
date back less than ten thousand years, which is only a moment in com-
parison with the millions of years of the geological eras or with the three
thousand million years during which the earth has existed as a separate
body. Even the great age of the earth is only a small fraction of the
enormous lifetime of a star.

Great distances, prodigious masses, and long intervals of time are not
merely interesting. They stir our imaginations, exercise our reasoning
powers, expand our spirits, and change our perspective with respect to
all the experiences of life. But they do not include all the important conse-
quences of astronomical investigations. Indeed, they do not directly
include that which is most important, the supreme discovery of science —
the orderliness of the universe.

What do we mean by "the orderliness of the universe"? Astronomers
found from painstaking and long-continued observations of the heavenly
bodies that celestial phenomena recur in regular sequences. Though the
order of the succession of events in the heavens is often somewhat com-
plex, it is nevertheless systematic and invariable. The running of no clock
ever approached in precision the motions of the sun, the moon, and the
stars. In fact, to this day clocks are corrected and regulated by comparing
them with the apparent diurnal motions of the heavenly bodies. Since not
merely a few but hundreds of celestial phenomena were long ago found
to be perfectly orderly, it was gradually perceived that majestic order
prevails universally in those regions in which, before the birth of science,
capricious gods and goddesses were believed to hold dominion. . . .

THE MOON

For a few days each month the crescent moon may be seen after sunset
in the western sky. In a week it changes to a semicircle of light directly
south on the meridian at the same hour; in another week, at the full
phase, it rises in the east as the sun sets. If observations are continued
through the night, the full moon is found directly south at midnight, and
setting in the west as the sun rises. Year after year and century after
century this shining body goes through its cycles of changes, each cycle
being generally similar to the others but no two of them being exactly
alike. It is not surprising that primitive peoples should have regarded it
with awe and determined the times of their religious ceremonies by its

64 THE HEAVENS

phases. Indeed, most of the calendars of antiquity were based upon the
phases of the moon.

Regularities in the motions of the moon and in the succession of its
phases have always been found by those who have carefully followed
celestial phenomena. But these approximations to cyclical repetitions are
only crude hints of the perfect orderliness which accurate and long-
continued astronomical observations have proved to exist. Every apparent
departure from some simple theory has been found to be a part of a
greater and more complicated order. The observed motion of the moon
is compounded out of more than a thousand cycles whose magnitudes
and phases are now accurately known. The theory of the motion of the
moon is so perfect that its position can be computed for any instant in
the future, even for a thousand years. Indeed, it is obvious that if it were
not possible for mathematicians to compute accurately the motions of the
moon, they could not unerringly predict all the circumstances of eclipses
many years in advance of their occurrence.

Astronomers have not simply worked out the properties of the motion
of the moon from observations of its positions over long intervals of time.
They have discovered the underlying reason for all the complexities of its
path about the earth, and that reason is that it moves subject to the
gravitational attraction of the earth and, to a lesser degree, of the more
distant sun. This force which prevents the moon from flying away from
the earth is sufficient to break a steel cable nearly three 'hundred miles
in diameter. Yet invisibly, like the force between a magnet and a piece of
iron, it acts across the 240,000 miles between the earth and the moon.
With extraordinary exactness it varies inversely as the square of the
distance between these bodies. Together with the attraction of the sun
on the earth and the moon, it forms an infallible basis for explaining all
the peculiarities of the motion of our satellite. Indeed, in numerous
instances it has enabled mathematicians to anticipate experience and to
predict phenomena which observations later confirmed.

Mere words cannot do justice to the marvelous agreement between
theory and the actual motions of the moon. No machine ever ran with
such accuracy; no predictions of terrestrial phenomena were ever so per-
fectly fulfilled. If we are entitled to conclude that we understand any-
thing whatever, we may claim that we understand how the moon moves
around the earth under the attractions of the earth and the sun. . . .

Evidently the moon is above the level of the highest clouds and far
away from the earth. It is easy to understand that if two astronomers are
at two different points, they will see the moon in somewhat different
directions from their points of observation: and it is almost as easy to

THE ORDERLY UNIVERSE 65

understand that from the distance between the astronomers and the
angle at which the moon is observed its altitude above the earth can
be computed. From such observations and calculations, astronomers have
found that the distance from the center of the earth to the center of the
moon varies between 225,000 and 252,000 miles, with an average of 238,857
miles. This distance is known with nearly the same percentage of accuracy
as the diameter of the earth. The moon moves at an average speed of
3,350 feet per second in an orbit so large that in going this distance it
deviates from a straight line only about one twentieth of an inch.

After the distance to the moon has been determined, its diameter can
be computed from its apparent size. This shining object which even a
small button held at arm's length will hide from view is actually 2,160
miles in diameter, or more than one fourth the diameter of the earth.
Its exterior area is approximately thirty million square miles, or ten
times the area of the United States. Consequently, there is abundant room
on its surface for mountains and valleys and plains and lakes and seas.
There are, indeed, many mountains on the moon's surface, both isolated
peaks and long ranges, and there are valleys and plains, but no lakes or
seas. In fact, there is no water whatever upon its surface, nor is there even
an atmosphere surrounding it.

There is no real mystery respecting the lack of air and water on the
moon. The surface gravity of this small world (about one sixth that of
the earth) is not sufficient to hold the swiftly darting molecules of an
atmosphere from escaping away into space. Its surface is a desert, unpro-
tected by clouds or an atmosphere from the burning rays of the sun
during its day, or from the rapid escape of heat during its night. Both
extremes of its surface temperature are particularly severe, because its
period of rotation is about 29.5 times that of the earth. For nearly fifteen
of our days a point on its surface is subjected to a temperature above the
boiling point of water on the earth; for an equal interval of time it freezes
in a temperature which descends far toward the absolute zero (about
—460° Fahrenheit), Evidently it cannot be the abode of life. . . .

THE PLANETS

From a certain point of view the earth is for us a very important body,
more important than every celestial body except the sun. It has been the
home of the life stream of which we are a part for more than a thousand
million years. It will be the home of our successors until our race becomes
extinct. Our very existence depends upon it.

From another point of view, which we shall now take, the earth is not
very important. It is only one of nine known planets which revolve

66 THE HEAVENS

around the sun, each of them held in its orbit by the attraction of the
great central mass. Thus, the very brilliant silvery object which we see
in the western evening sky (and eastern morning sky) every nineteen
months is the planet Venus, a world in size and in most other respects
similar to our earth. The wandering conspicuous red body which appears
in the evening sky every twenty-six months is the planet Mars, and the
brighter yellowish object which returns every thirteen months is Jupiter.
These bodies and two others, Mercury and Saturn, were called planets
(or wanderers) by the ancients because they are constantly moving with
respect to the stars. . . .

It was not until the first decades of the seventeenth century that Kepler
worked out from the observations of Tycho Brahe the properties of the
planetary orbits; it was not until the latter part of the same century that
Newton proved the law of gravitation and explained by means of it the
motions of the planets and of the moon, the oblateness of the earth, and
the ebb and flow of the tides. These great achievements mark the closing
of an epoch in the history of the thought of the world and the beginning
of a new, for they entirely overthrew earlier views respecting the nature
of the cosmos and established others which were entirely different. They
permanently removed man from his proud position at the center of crea-
tion and placed him on a relatively insignificant body; but, as a compen-
sation, they rescued him from a universe of chance and superstition and
gave him one of unfailing and majestic orderliness.

There have been many impressive illustrations of the orderliness of
the universe and of our understanding of that order, but none has been
more dramatic than the discovery of Neptune. This remarkable story
opened in 1781 with the discovery of the planet Uranus (the first one
discovered in historic times) by William Herschel; it closed with the
discovery of Neptune in 1846.

After Uranus had been observed for a few months, mathematicians
computed its orbit and directed observers where to point their telescopes
in order to see this planet, for it is too faint to be observable with the
unaided eye. For nearly forty years Uranus was always found precisely
where the mathematicians said it would be seen. Then there began to be
an appreciable difference between theory and the observations. By 1830
the discrepancies had become serious; by 1840 they were intolerably large.
Although the discrepancies were intolerably large to scientists they would
have been negligible to anyone else in the world. During the sixty years
following the discovery of Uranus it did not depart from its predicted
positions by an amount large enough to be observable without the aid
of a telescope. Since mankind had never even known of the existence

THE ORDERLY UNIVERSE 67

of Uranus until 1781, it at first seems absurd that scientists should have
been disturbed by very minute unexplained peculiarities in its motions —
variations from theory so slight that they were not observable until the
lapse of about forty years. The theories, however, were believed to be
very perfect. Hence the discrepancies called into question their exactness,
or perhaps even the soundness of mathematical reasoning. In fact, the
unexplained difference between theory and observation threw a doubt
on our ability to discover and to apply the laws of nature. For this reason
the motion of Uranus became one of the most important problems in
science.

In 1846 order was restored by a brilliant discovery. Some years earlier
it had been suggested that Uranus was departing slightly from its pre-
dicted orbit as the consequence of the attraction of an unknown world. The
problem was to find the unknown body from its minute effects on Uranus.
No brief statement can give any adequate realization of the difficulties
of the problem. The leading mathematicians of the time thought it could
not be solved. But two young men, J. C. Adams, of England, and U. J.
Leverrier, of France, inspired with the optimism and energy of youth,
calculated where the unknown world would be found. Their predictions
were brilliantly fulfilled by the discovery of Neptune on February 23,
1846, by J. G. Galle, a young German astronomer. With this discovery,
the motion of Uranus again was fully explained, the laws of nature and
our reasoning powers were no longer in question, and the universe was
once more orderly. . . .

No experiences give us a better understanding of distances than those
obtained from long journeys. Consequently, let us in imagination board
some miraculous skyship, of which everyone has often dreamed, and
travel from the sun to the various planets.

Obviously our skyship must fly rapidly or we shall not live long enough
to cross the great distance from one planet to another. On the other hand,
if it travels at too great speed we shall not be able to descend safely upon
the surface of a planet. So let us suppose our skyship can traverse the
interplanetary spaces at the rate of a thousand miles per hour, a speed of
travel at which one might eat breakfast in the eastern part of the United
States and luncheon in Europe. Let us start from the surface of the sun.
Perhaps before directing our way toward Mercury we should circle around
this great center of attraction. Jauntily we set out and travel continuously,
but we do not complete the circuit of the sun and get back to our point
of departure until 113 days, or nearly four months, have elapsed.

With some trepidation at leaving the sun and plunging into the inter-
planetary spaces, we depart for Mercury, which we reach in four years and

68 THE HEAVENS

one month. In three and one half years we are at the distance of Venus;
in three more at the orbit of the earth, ten years and seven months after
we left the sun. Since five years and seven months more are required to
reach Mars from the orbit of the earth, it takes our skyship sixteen years
and two months to fly from the sun to this planet. Obviously the intervals
of time required for these sky voyages are so great that they fail to give us
any real understanding of the enormous distances we traverse. Yet let us
continue* on our way.

We arrive at Jupiter in fifty-five years after we left the sun; at Saturn in
lor years; at Uranus in 203 years; and at Neptune in 318 years. If we
should continue to distant and inconspicuous Pluto, we should arrive there
in 420 years. And yet at the rate of our travel we could eat breakfast in
New York, luncheon in London, and return to New York for dinner anc
the theater. . . .

COMETS

Since the* dawn of history and, indeed, for millions of years before the
origin of man, the sun and the moon have not changed appreciably in
appearance. But there are celestial visitors, the comets, which do not
possess these qualities of permanence and uniformity from which the
orderliness of the universe was first perceived. These objects often come
quite unexpectedly out of the depths of space for a brief visit to the inte-
rior of the solar system, and then they recede back into the night from
which they came. They are not of fixed shape or constant dimensions like
the planets. The typical comet consists of a small nucleus, generally star-
like in appearance, surrounded by a vast gaseous envelope which varies
enormously in volume, sometimes being as large as the sun; while from its
head there streams out a tail, perhaps fifty millions of miles in length,
which in exceptional cases appears to reach a third of the way across the
sky.

It is not strange that primitive peoples and, indeed, all men until only
two or three centuries ago regarded comets with superstitious fear. Our
predecessors believed that these bizarre-appearing objects are malignant
spirits prowling through our atmosphere, or at least that they are portents
of wars and pestilences. After centuries of belief in these superstitions,
accepted alike by the ignorant and the learned, by theologians and
scientists, observations led finally to the truth.

Tycho Brahe (1571-1630), the greatest and last observer before the inven^
tion of the telescope, comparing the different apparent directions of the
comet of 1577 as seen simultaneously from various places in Europe,
proved that this terrifying object was far beyond our atmosphere and at

THE ORDERLY UNIVERSE 69

least as distant as the moon. By this demonstration he removed comets
from the apparent vagaries of atmospheric phenomena to the orderly
domains of the celestial bodies.

It should not be thought that comets and thqjr motions were at once
completely understood. The phenomena they present are far too com-
plicated for an easy explanation. In fact, the determination of the proper-
ties of their paths through the solar system had to await Newton's dis-
covery of the law of gravitation in 1686 and his use of it in explaining the
celestial motions. He devised methods of determining the orbits of comets,
however elongated they might be.

A lifelong friend of Newton, Edmund Halley, applied Newton's
methods to computing the orbit of a great comet which had been observed
in 1682. After an enormous amount of work on this and earlier comets,
he proved that it revolves in a very elongated path, returning to the neigh-
borhood of the sun about every seventy-five years. He concluded that it
was identical with comets which had been observed in 1456, 1301, 1145*
1066, and at various other times; he boldly predicted it would return
in 1759, and it did. It came again according to predictions in 1835, and
most recently in 1910. Now it is far out in its long orbit. It has been
invisible for twenty-five years and will not be seen again for forty years
in the future. Yet mathematicians can follow it with perfect certainty,
and long before its next return they will compute the very day when it
will arrive at the point of its orbit nearest the sun.

. . . Comets differ enormously from one another in brightness, volume,
length of tails, and internal activity. From three to eleven comets are
observed each year, nearly all of them being so faint as to be invisible
without optical aid. Occasionally one appears which is bright enough to-
be easily visible to the unaided eye; about three or four times a century
a very great one becomes the most conspicuous object in the night sky.
The tails of comets develop and increase in length as these objects
approach the sun and diminish and disappear as they recede again*
While a comet is approaching the sun, its tail streams out behind; as.
it recedes, its tail projects out ahead of it. ...

THE SUN

In comparison with the universe in general, only one object in the
solar system is worth mentioning, and that object is the sun. It is a
million times greater than the earth in volume and a thousand times
greater in mass than all the planets combined. It holds the little planets
under its gravitative control, it lights and warms them with its abun-
dant rays, it takes them with it in its enormous excursions among the stars.

70 THE HEAVENS

How brilliant the light of the noonday sun is! In comparison with it
all artificial lights are feeble and dull. How intensely it warms the sur-
face of the earth on a summer's day! This general impression is not
erroneous, for accurate jneasurements prove that when its rays fall per-
pendicularly upon the surface of the earth radiant energy is received
from it at the rate of 1.5 horsepower per square yard. Under the same
condition of perpendicular rays, a square mile of surface receives radiant
energy from the sun at the rate of 4,646,400 horsepower, or at the rate of
330 million million (330,000,000,000,000) horsepower on the whole earth.
If this energy were divided equally among the two billion human beings
now living on the earth, each of them would have more than a hundred
thousand horsepower for his use.

As enormous as is the energy received by the earth from the sun, it is
trivial compared with the amount radiated by the sun, for the earth as
seen from the sun would appear to be only a point, somewhat smaller
than Venus appears to us when it is the bright evening star. It is evident
that such a distant and apparently insignificant object would intercept only
a very small fraction of the solar energy streaming out from it in every
direction. It is found by computation that the earth intercepts only one
two-billionth of the energy radiated by the sun. Otherwise expressed, the
sun radiates more energy in a second than the earth receives in sixty years.

Obviously the sun must be very hot, for otherwise it would not radiate
energy at an enormous rate. By several methods it is found that the tem-
perature of its exterior radiating layers is about ten thousand degrees
Fahrenheit, or far beyond the temperature required for melting and
volatilizing iron and other similar substances. In its deep interior the
temperatures are enormously higher, mounting to at least several million
degrees.

The temperature of the sun's interior has not, of course, been measured
by any direct means, for the depths of the sun are quite inaccessible to us.
But science often penetrates inaccessible regions by reasoning, as it does
in this case. The general principles underlying the method used in this
problem are as follows: Each layer of the sun weighs down upon the one
directly beneath it and tends to compress it. This tendency to compression
of a layer is balanced by the expansive forces due to its temperature. Now
the rates of increase downward in both density and temperature can be
determined by the condition that the entire mass of the sun shall be in
equilibrium. The results are subject to some uncertainties, however, because
of our lack of knowledge of the properties of matter under the extreme
conditions of pressure and temperature prevailing deep in the sun.

When we recall the terrestrial storms that are produced by unequal

THE ORDERLY UNIVERSE 71

heating of different portions of the earth's atmosphere, we naturally ex-
pect extremely violent disturbances on the sun. The wildest flights of our
imagination, however, never approach the realities, for often masses of
enormously heated gases a hundred times greater than the earth in volume
shoot upward from its surface, sometimes farther than from the earth
to the moon. Particularly in intermediate latitudes on each side of the solar
equator there are storm zones in which great whirling sun spots appear.
These sun-spot disturbances, ranging from a few thousand up to more
than a hundred thousand miles in diameter, have centers which appear
dark in contrast to the surrounding bright surface, though they are more
luminous than the filament of an electric light. In them incandescent gases
surge and billow, and from their borders eruptions to great altitudes are
particularly abundant. If our earth were placed on the surface of the sun
it would be tossed about like a pebble in a whirlpool; it would be melted
and dissipated like a snowflake in a seething lake of lava. . . .

If the sun were dissipating its mass into space, scientists would natu-
rally inquire how it is restored, but until about 1850 they did not ask
the same question respecting the energy it radiates. Until that time they
did not realize that energy is something quantitative and measurable, and
hence that its origin requires explanation. The sun cannot be a body which
was once much hotter than at present and which is slowly cooling off,
for if this were all there is to its heat it would not have lasted a thou-
sandth of the long periods of the geological ages. It cannot be simply
burning, for the heat produced by its combustion, even if it were composed
of pure coal and oxygen, would last only a few thousand years. If it
were contracting, the heat generated in the process would maintain its
radiation only a few million years, which is less than one per cent of the
interval during which it has shed its warm rays upon the earth at approxi-
mately the present rate.

Recently very conclusive reasons have been found for believing that the
energy the sun radiates is due to transformations of its elements, partic-
ularly of hydrogen, into heavier elements, and probably to the transforma-
tion of matter into energy in accordance with Einstein's principle of the
fundamental equivalence of mass and energy. These sources of energy are
of an entirely different and higher order of magnitude than any hereto-
fore considered by scientists. Although the mass equivalent of the energy
radiated by the sun in a second is over 4,000,000 tons, the mass of the sun
is so enormous that it will not be reduced through radiation by so much
as one per cent in 150,000,000,000 years. Consequently, it is not surprising
that the geological evidence is conclusive that the earth has received solar
energy at substantially the present rate for perhaps a thousand million

72 THE HEAVENS

years. Even this long interval of time is only a very small fraction of the
period during which the earth will continue in the future to be lighted
and warmed by the sun almost precisely as it is at present. The fears once
held that in a few million years the light of the sun will fail have proved
groundless, and scientists no longer look forward to a time when the earth,
cold and lifeless, will circulate endlessly around a dark center of attraction.

One of the miracles of science has been the determination of the composi-
tion of the sun. . . . The normal ear has the ability to distinguish separately
a mixture of a considerable number of tones. The eye has no correspond-
ing power — a mixture of blue and yellow, for example, appears as a
single color (green) and not as a combination of two colors. Fortunately,
a very remarkable instrument, the spectroscope, separates a mixture of light
into its component colors, or wave lengths, and enables the astronomer
to determine precisely what wave lengths are present in the radiation
from the sun, or, indeed, from any other celestial body from which
sufficient radiant energy is received. . . .

Of the ninety elements known on the earth, at least fifty have been found
to exist in the atmosphere of the sun in the gaseous state, and the presence
of several others is probable. The elements found in considerable abun-
dance in the sun include hydrogen, helium, oxygen, magnesium, iron,
silicon, sodium, potassium, calcium, aluminum, nickel, manganese,
chromium, cobalt, titanium, copper, vanadium, and zinc. Some of the
heaviest elements, such as gold and uranium, have not been found in the
sun's atmosphere, perhaps because they lie at low levels. . . .

THE STARS

As the sun rises, all the sparkling stars which sprinkle the clear night
sky pale into insignificance and totally disappear. Yet actually they are suns,
most of those which are visible to the unaided eye being much greater
than our own. Indeed, some of them radiate thousands of times as much
light, and a few are known which are millions of times greater in volume.
Their apparent insignificance is due to their incomprehensibly enormous
distances.

In order to bring within the range of our understanding the distance
from the sun to the earth, we computed the time necessary for an
imaginary skyship to travel from one of these bodies to the other at the rate
of a thousand miles per hour. We found that if it continued on its way
night and day, without pausing, it would require ten years and seven
months to traverse the ninety-three million miles between the center of
our system and this little planet of ours. Even with the aid of this calcula-
tion we do not grasp the significance of the distances in the solar system.

THE ORDERLY UNIVERSE 73

Perhaps we shall improve our understanding of the distances in the
solar system by noting that the velocity we assumed for our skyship was
more than 30 per cent greater than that of sound in our atmosphere, for
sounds travels at the rate of only 736 miles per hour. Let us assume that
sound could come from the sun to us at this speed. Then, if we should
see some tremendous solar explosion and should expectantly await its
thunders, we should be held in suspense before hearing *it for more than
fourteen years.

If we fail to comprehend the great distances between the members of
our solar system, we naturally shall fall far short of grasping as realities
the enormously greater distances to the stars. Yet we must attempt to do
so, and we shall find that our understanding of these distances increases as
we struggle with them. Let us start with the nearest star visible without
optical aid from northern latitudes, the brilliant Sirius, the brightest
star in all the sky. This beautiful bluish-white object is on the southern
meridian at eight o'clock in the evening about the first of March each
year. Astronomers have found by measurements that its distance is 51,700,-
000,000,000 miles, or more than 550,000 times the distance from the sun to
the earth. Therefore, more than 6,000,000 years would be required for
our imaginary skyship to fly from the solar system to Sirius.

In view of the enormous distances to even the nearest of the stars, we
naturally wonder how astronomers have measured them and whether,
after all, they are not merely conjectures resting upon no substantial
foundation. The method of determining the distances of the relatively
near stars is essentially the same as that used in determining the distance
to the moon, namely, measuring the differences in their directions as seen
from two different points. At some convenient time in the year the star
Sirius, for example, is observed to be in a certain direction from the
earth. A few months later, after the earth has moved many millions of
miles in its orbit, Sirius is found to be in a slightly different direction.
From this change in direction and the distance apart of the two points
of observation the distance of Sirius is readily computed. Obviously, the
method is entirely sound, and in the case of a star no more distant than
Sirius it is known that the results are not uncertain to more than about
one per cent of their value.

Although the direct method of measuring stellar distances is relatively
simple, the difficulties of putting it into effect are in general enormous be-
cause of the remoteness of the stars. Indeed, the greatest observed differ-
ence in direction of Sirius as observed from the earth from two points in
its orbit separated by as great a distance as even that from the earth to the
sun is extremely small. It is as small as the difference in direction of an

74 THE HEAVENS

object twenty-two miles away wher viewed first with one eye and then
with the other. Moreover, only four or five other known stars, all of which
except one are so faint as to be invisible without optical aid, are as near to
us as Sirius. Indeed, all except a few hundred stars out of the millions
which can be photographed through large telescopes are so very remote
that their distances cannot be measured by the direct method which has
been outlined. Nevertheless, our knowledge of the distances of the stars
does not stop with this limited number, for astronomers with extraor-
dinary skill have used their knowledge of the distances and other prop-
erties of these nearer stars as a basis for several other methods which
reach enormously farther into space.

Before taking up the characteristics of the stars we shall define a more
convenient unit for stellar distances which we shall often have occasion to
use. It is the distance light travels in interstellar space in a year, known as
the light-year. Since light travels in a vacuum at the rate of about 186,000
miles per second, the light-year is 5,880,000,000,000 miles, or about 60,000
times the distance from the sun to the earth. The star Sirius is distant 8.8
light-years; the stars of the Big Dipper are distant 70 to 80 light-years;
the Pleiades, about 200 light-years; the brighter stars in Orion, about 500
light-years; and the star clouds which make up the Milky Way thousands
of light-years.

In spite of the enormous distances of the stars a great deal has been
learned about them as individual bodies. In the first place, they consist
of a number of classes depending upon the properties of the light they
radiate as determined by the spectroscope. At one extreme are the blue
Class B stars, of which a number of the brighter stars in Orion are exam-
ples. These stars, which radiate many thousand times as much light as
our sun, are enormous bodies whose exterior atmospheres are at tem-
peratures ranging from 80,000 to 100,000 degrees Fahrenheit. In their
atmospheres are spectral evidences of only hydrogen, helium, oxygen, and
nitrogen.

Next come the Class A stars, which are not quite so hot or brilliant as
the Class B stars. Sirius is a splendid example of this class. Its surface
temperature is nearly twice that of the sun, and it radiates twenty-seven
times as much light. Then follow the Class F stars, of which Canopus and
Procyon are illustrations. These stars approach in temperature, brilliance,
and composition the Class G stars to which Capella and the sun belong.
Nearly half of all the stars in the catalogues of stellar spectra are closely
related to the sun. Only a few are giants of Class A, and a still smaller
number are supergiants of Class B.

Beyond the stars in the spectral sequence of class G, to which the *un

THE ORDERLY UNIVERSE 75

belongs, come the cooler and ruddier stars of Class K, of which Arcturus
and Aldebaran are notable examples. So far the stars of each spectral
class connect by insensible gradations with those of the next class. But at
the stars of Class K there is a discontinuity. The next class in the order
in which they are usually given are those of Class M, of which Betelgeuse
and Antares are examples. The atmospheres of these stars are at relatively
low temperatures, as would naturally be inferred from their colors, and
they contain many compounds as well as individual chemical elements.
There are three other classes of stars, classes N, R, and S, which have no
well-defined relationship to the other classes. They are all faint, with one
or two exceptions being far beyond the range of the unaided eye, they
are very few in number, and they are deep red in color. , . .

In 1650, forty years after the invention of the telescope by Galileo, the
star at the bend of the handle of the Big Dipper, which theretofore looked
like an ordinary star, was found to consist of two stars apparently almost
touching each other. It is now known, however, that these two stars are
hundreds of times as far apart as are the earth and the sun. The discovery
of this pair has been followed by the discovery of nearly 20,000 other
double stars. Probably a few of these double pairs consist of two unrelated
stars which happen to be for a time almost in the same direction from
us, but in nearly all cases they are actually twin suns revolving around
their center of gravity. The periods of revolution of most of them are so
long, however, that they have not been determined from observations in
the relatively short intervals since their discovery. . . .

In certain cases the plane of revolution of a double star passes through or
near the present position of the solar system. It is clear that when the two
stars of such a pair are in a line with the earth, one wholly or partially
eclipses the other, and at such times the light received from the pair is
temporarily reduced. If the two stars are equal in volume and equally
bright, the light received by the earth at the time of eclipse is one half
its normal value. If one star is totally dark, it may entirely eclipse the
luminous star. It is evident that many cases are theoretically possible, and
it is an interesting fact that nearly all of them have been observed.

It is clearly not difficult to determine the periods of revolution of these
variable stars, as they are called, for their periods are defined by the inter-
vals between their eclipses. But to determine the distance between the
components of such a pair is quite another matter, for they are so close
together that they appear to be a single star. Fortunately, a remarkable
application of the spectroscope, which cannot be explained here, enables
the astronomer to measure the relative velocity of a pair in their orbit;

76 THE HEAVENS

and from this velocity and the period of revolution of a pair he computes
the perimeter of their orbit, and then their distance apart. . . .

Many stars, however, are variables as a consequence of change in the
rates of their radiation. In certain cases the variations in brightness are
nearly as regular as those of eclipsing variables, though the changes are
otherwise quite different. In other cases the variations in brightness are
irregular and through wide ranges. For example, the star Omicron Ceti
is at least ten thousand times brighter at its highest maxima than at its
lowest minima. . . .

The extreme limit in variable stars is reached by the temporary stars,
or novae. These stars blaze out suddenly from obscurity to great brilliance,
in some cases increasing their radiation a hundred-thousandfold in a day
or two, only gradually to sink back to relative obscurity within a few
months. A number of these remarkable temporary stars have played
important roles in the history of astronomy. For example, the Greek
philosopher and astronomer Hipparchus (about 160-105 B.C.) made the
earliest known catalogue of stars, 1080 in number, in order to determine
whether all stars are as transitory as the nova which he observed. Another
temporary star inspired Tycho Brahe (1546-1601) to become an observer,
and another which appeared in 1572 aroused the interest of Kepler in
astronomy.

We do not know the cause of the remarkable outbursts of the novae,
which are more violent phenomena on a stellar scale than any of the little
explosions which ever take place on the earth or even than the much
greater ones on the sun. If our sun should ever become a temporary star,
our earth and the other planets would be quickly destroyed. It seems
probable, however, that only certain stars are subject to these mighty
outbursts, and that they occur again and again, separated by long intervals.
These cataclysmic phenomena teach us how little we know of violent
forces, even when we observe enormous volumes of incandescent gases
shoot up hundreds of thousands of miles from the surface of the sun.

NEBULAE

There are among the stars many faint, hazy patches called nebulae, or
little clouds. Some of them, such as that around the central star in the
Sword of Orion, are faintly visible to the unaided eye, but most of them
are found only with telescopic aid or by photography. They look like
tenuous gaseous masses, and for a long time they were thought to be
gaseous in nature, perhaps primordial world stuff out of which stars
evolve in the course of enormous periods of time. With more powerful
telescopes, however, a few of them were resolved into separate stars.

THE ORDERLY UNIVERSE 77

Then for a time it was supposed that probably all nebulae are swarms
of stars which can be resolved by sufficiently powerful instruments. But
toward the close of the nineteenth century this conjecture was proved by
the spectroscope to be false, for when their light was examined by this in-
strument it was found to have the properties of light radiated by luminous
gases rather than by relatively dense stars. Consequently, we now know
that the nebulae, except those which are now classed differendy, are
tenuous gases. . . .

OUR STELLAR SYSTEM

We have found that our earth is a member of a family of planets. Now
we inquire whether our sun is similarly a member of a family of stars.

When we attempt to determine whether the stars are the components
of some vast organism, we are at once confronted with serious difficulties
because of their great distances apart. For example, the distance between
our solar system and the nearest known star, the far southern Alpha
Centauri, is 4.3 light-years, or more than 25,000,000,000,000 miles. The
nearest bright star visible from northern latitudes is Sirius at a distance
of 8.8 light-years. Most of the stars within the range of the unaided eye
are many times as far away as Sirius, while most of those photographed
with large telescopes are distant more than a thousand light-years. . . .

Let us first consider the stellar density near the present position of the
solar system where the results are most trustworthy. Since it is possible
with modern instruments and photographic processes to measure with
much precision the distances of stars within thirteen light-years (76,000,-
000,000,000 miles) of the sun, we shall first examine this region around
the sun. Within this sphere of thirteen light-years in radius there are thirty
known stars, five of which are doubles and one of which is a triple. It
would be natural to expect that these relatively near stars would be in-
cluded among the hundred brightest stars in the sky. As a matter of fact,
only six of them, besides the sun, are bright enough to be visible without
optical aid, while several of them are of such low luminosity that they are
very faint in spite of their small distance from us, astronomically speaking.
Since several of these near faint stars are of recent discovery, it is probable
that there are a few others, at present unknown, which are within thirteen
light-years of our sun. For the sake of having a definite number to serve
as a basis for our calculations, we shall assume that there are thirty-five
stars within this sphere. . . .

It should not be understood that the thirty-five stars we are considering
form a system in any special sense. They are simply a small sample out
of an ocean of stars and give us some idea respecting what the general

78 THE HEAVENS

stellar system is like. At present the stars in this sphere arc near one
another, but their neighborliness is only transitory, for they are moving in
various directions at various velocities, and their mutual gravitation lacks
much of being sufficient to hold them together. In a million years they
will be far from one another and will have formed entirely different close
associates.

There are, however, families of stars in the sense that they permanently,
or at least for millions of millions of years, form a dynamical system of
mutually interacting bodies. The best-known of such families is the
Hyades stars in the constellation Taurus. About eighty of these stars are
moving together through the celestial regions like a flock of migratory
birds across the sky. Their spectra prove that they are similar in constitu-
tion, they undoubtedly had a common origin, and they are undergoing
parallel evolutions. . . .

There are several hundred other known clusters of stars besides the
Hyades family. Some of them are open groups like the Big Dipper and
the Sickle in Leo. Others are more closely related families like the Pleiades,
and in a few clusters the stars appear to be actually crowded together,
although those which are nearest each other are rarely separated by less
than a light-year. . . .

Our sun does not appear to be a member of a compact (in the astronom-
ical sense) family of stars, but it is a member of an enormous star cloud
containing millions of stars. In these larger organizations the stars do
not exhibit the similarities which are found among the stars of such
compact families as the Hyades. Nor are they moving in parallel lines at
the same speed. They consist, rather, of stars of all classes and kinds,
moving around among one another somewhat like bees in a swarm,
doubtless held loosely together by their mutual gravitation. These great
star clouds largely make up the Milky Way. Even with the unaided eye
they loom up conspicuously, under favorable conditions, in Cygnus,
Sagittarius and Scorpius. With a photographic telescope their soft mist
is resolved into myriads of stars. . . .

When we pass beyond the star cloud of which the sun is a member, we
arrive at our entire Milky Way system, or galaxy. It is composed of vast
clouds of stars and millions of individual stars spread out in the form
of a disk, the diameter of which is of the order of 60,000 light-years and
the thickness of which is perhaps one eighth as great. It is not to be under-
stood that our galaxy is homogeneous with well-defined exterior surfaces.
It is, rather, a somewhat irregular assemblage of star clouds and individual
stars, with vast regions of relatively high steller density, always decreasing,
however, toward its borders. If the average stellar density of the galactic

THE ORDERLY UNIVERSE 79

system were as great as it is within thirteen light-years of the sun, there
would be in our galaxy more than 50,000,000,000 stars. Although this
number may be somewhat too large, it is probable that there are several
billion stars in our Milky Way system, and the number of them may
exceed even fifty billions. It is interesting that heretofore estimates of
astronomers have always fallen short of the actualities, as have conjectures
in other fields of science.

If the solar system were at the center of the galaxy, the stars would be
symmetrically distributed around the Milky Way. The stars are, however,
much more numerous in the direction of Sagittarius and Scorpius than in
the opposite part of the heavens. This fact means that the galactic center
is in the direction of these constellations, perhaps at a distance of a few
thousand light-years. Moreover, the sun is some distance, perhaps a few
hundred light-years, north of the central plane of the galaxy, a result
which is inferred from the observed fact that stars are somewhat more
numerous on the south side than they are on the north side of the great
circle representing, at least generally, its central line. This is the position
of the solar system at present, but the sun is moving obliquely northward
from the galactic plane at the rate of a light-year in fifteen or twenty
thousand years. Consequently, if it maintains its velocity and direction
of motion for a million years, it will then be in a substantially different
part of our galaxy.

Our stellar system owes its disklike shape to its rotation, an inference
which is based on dynamical principles and which has been verified by
observations. Astronomers long ago proved the revolution of the earth
around the sun by observations of the distant stars. Now they are proving
the rotation of the enormous galaxy by measurements of velocities toward
or from systems of stars far beyond its borders. ... In spite of all the
variety in the motions of its stars and star clouds, it on the whole is
involved in an immense gyration. At the distance of the sun from its
center the velocity of its rotation is probably of the order of one or two
hundred miles per second, and the period of its rotation between fifty and
two hundred million years. It follows that during the long intervals of
the geological eras our earth in its motion with the sun has traveled
widely throughout our galactic system. . . .

GLOBULAR CLUSTERS

Somewhat outside of our galactic system, at distances ranging from
25,000 to 160,000 light-years, there are approximately a hundred great
aggregations of stars which are called globular dusters because they are
almost exactly spherical in iorm. At the distances of these clusters only

80 THE HEAVENS

giant and supergiant stars are separately visible even through large tele-
scopes. Consequently, those of their stars which are observed or photo-
graphed as separate objects are only a very small fraction of all the stars
which they contain. Yet the separately observed stars in the globular
clusters are numbered by thousands and tens of thousands, and the fainter
ones almost certainly number hundreds of thousands and probably
millions.

One of the few globular clusters visible to the unaided eye is the Great
Cluster in Hercules. At its distance of 33,000 light-years the combined
light of 400,000 stars, each equal to our sun in luminosity, would be hardly
visible to the unaided eye. Hence this cluster must be composed of an
enormous number of stars and many of high luminosity. Indeed, on a
photograph of it taken with one of the great telescopes on Mount Wilson,
the images of 40,000 stars were counted, the faintest of these stars being
approximately a hundred times as luminous as our sun. Consequently,
there can be little doubt that this immense system contains at least a
million stars as great as our sun, and probably many millions of lower
luminosity. Yet it is so far away in the depths of space that we receive
from all its millions of suns less than one sixth as much light as we
receive from the North Star.

. . . Assume that the Hercules cluster contains a hundred thousand
giant and supergiant stars and a million stars altogether. We find from
its distance and its apparent diameter that its actual diameter is about
one hundred light-years. Hence it follows that if its hundred thousand
great stars were uniformly distributed throughout its volume, the average
distance between those which are adjacent would be more than two light-
years, or about 140,000 times the distance from the sun to the earth. If
we include the million stars in our computation, we find that the average
distance between neighbors is about one light-year. . . . Even the giant
stars in the clusters are no brighter as seen from one another than Venus
is as observed from the earth.

The globular clusters are dynamically mature; that is, they have
arrived at a state in which as a whole they remain unchanged, although
their individual stars are in ceaseless motion. Since many other aggre-
gations of stars, such as our galaxy and its star clouds, are very irregular
in structure, it does not seem probable that the globular clusters have
always had their present perfect symmetries. Perhaps better support for
our opinion that the stars in them were once irregularly distributed is
found in the exterior galaxies which are usually, but not always, far from
symmetrical.

If the present nearly spherical forms of the globular clusters are due

THE ORDERLY UNIVERSE 81

to dynamical evolutions, we may inquire how great must have been the
interval o£ time between some earlier, heterogeneous state and their present
conditions. We first find the astonishing result that the period of the
circuit of a star around the Hercules cluster, or from near its exterior
deep into its interior and out again somewhere else, is of the order of ten
million years. We next note that the dynamical evolution which we are
considering is due primarily to the near approaches of the stars, just as
the uniform distribution of molecules of various kinds in a gas is due
primarily to their collisions which occur with great frequency; indeed,
on the average, five thousand million times a second.

The distances between the stars in the clusters are so great that, on the
average, a star will make ten thousand circuits before it will pass near
enough another star to have the direction of its motion changed by as
much as twenty degrees. That is, on the average it moves for a hundred
thousand million years (ten thousand times ten million years) as though
the mass of the cluster were not concentrated into stars. Then it passes so
near one of these concentrations of mass (one of the stars) that the
direction of its motion is appreciably changed. After a very large number,
perhaps a million, of these adventures all the earlier heterogeneities are
smoothed out with a resulting globular cluster of stars. That is, the very
organization of the globular clusters proves that these spherical masses
of stars have been undergoing independent evolutions for at least millions
of millions of years. In the course of time, however, these symmetrical
structures may pass near or through somewhat similar aggregations and
be transformed into spinning irregular spirals similar to our galaxy,

EXTERIOR GALAXIES

We have often called the Milky Way system of stars "our" galaxy, as
though it were something we possess, or which is at least in our immediate
neighborhood. From the standpoint of the earth or even of the whole solar
system our language has been presumptuous, for we have explored tens
of thousands of light-years, or hundreds of millions of times the distance
from our planet to the sun. . . . But all these objects are of secondary
importance and interest in comparison with the enormous galaxy known
as the Great Nebula in Andromeda. Until within a few years astronomers
gazed up at this hazy patch of light, which is just within the range of
the unaided eye, and thought they were looking only at a tenuous nebula
lying out toward the borders of our stellar system. Now they know that
what they have been seeing is a great exterior galaxy, which in magnitude,
in number of stars, and in structure is similar to our own.

The distance from our present position to the Great Nebula in An-

82 THE HEAVENS

dromeda is about 900,000 light-years. Consequently, we see this galaxy
not as it is now but as it was before our ancestors evolved to the level
of men. . . . The so-called Andromeda nebula is actually a galaxy in
every essential respect similar to our own, a much flattened disk of many
billions of stars, having a diameter of something like 80,000 light-years
and rotating in a period of perhaps 150,000,000 years.

There are within a million light-years of the solar system six known
galaxies, including our own. But outside of this great sphere there are
hundreds of thousands of other galaxies within easy reach of large photo-
graphic telescopes. . . .

From atoms to galaxies each physical unit is made up of smaller units —
atoms of protons and electrons, molecules of atoms, stars of molecules,
galaxies of stars. We naturally inquire whether the galaxies we observe
are not components of still greater cosmic units; whether our Milky Way
system, for example, the Magellanic Clouds, the Andromeda galaxy and
others which are relatively near are not the constituents of a supergalaxy
enormously greater than any one of them, and perhaps millions of light-
years in diameter. Although the field which we are considering is rela-
tively new, astronomers have already found numerous aggregations of
galaxies into supergalaxies. For example, Harlow Shapley has described
a supergalaxy in the direction of Centaurus, but a hundred and fifty
million light-years beyond the stars of this constellation, which is com-
posed of more than three hundred galaxies, all of which are probably
comparable to our own steller system. The space occupied by this super-
galaxy is an oval about seven million light-years in length and two million
light-years in diameter. It is so vast that the average distance between
those of its galaxies which are adjacent is approximately a million light-
years.

What is beyond the supergalaxies? There is no observational evidence
bearing upon the question. There are good theoretical reasons, however,
for concluding that they do not extend on through an infinite space with
the approximate frequency which is found within a few hundred million
light-years of our own galaxy. According to certain deductions from the
theory of relativity they are limited in number, and space itself is limited
in extent. On the other hand, the supergalaxies which we now know
may be the component units of enormously greater supergalaxies of the
second order. And these supergalaxies of the second order may be the
constituents of supergalaxies of the third order, and so on upward in an
unending sequence. And, just as molecules are composed of atoms, and
atoms of protons and electrons, so protons and electrons may be made up

IS THERE LIFE ON OTHER WORLDS? 83

of still smaller units, and so on downward in an unending sequence of
units.

Naturally, it is unsafe to draw any positive conclusions respecting super-
galaxies of higher order or respecting subelectrons, for direct evidence
is lacking and we can reason only by analogy. It is even more hazardous
to speculate regarding a creation of the physical universe, for observa-
tional evidence is equally lacking, and there is not even analogy as a
guide. Consequently, though science has placed us on an eminence from
which we see very far, beyond our horizon there still lies a challenging
unknown.

Is There Life on Other Worlds?

SIR JAMES JEANS

CJO LONG AS THE EARTH WAS BELIEVED TO BE THE
*^ center of the universe the question of life on other worlds could
hardly arise; there were no other worlds in the astronomical sense, although
a heaven above and a hell beneath might form adjuncts to this world.
The cosmology of the Divina Commedia is typical of its period. In 1440
we find Nicholas of Cusa comparing our earth, as Pythagoras had done
before him, to the other stars, although without expressing any opinion as
to whether these other stars were inhabited or not. At the end of the next
century Giordano Bruno wrote that "there are endless particular worlds
similar to this of the earth." He plainly supposed these other worlds — "the
moon, planets and other stars, which are infinite in number" — to be
inhabited, since he regarded their creation as evidence of the Divine
goodness. He was burned at the stake in 1600; had he lived only ten years
longer, his convictions would have been strengthened by Galileo's discovery
of mountains and supposed seas on the moon.
The arguments of Kepler and Newton led to a general recognition that

84 THE HEAVENS

the stars were not other worlds like our earth but other suns like our sun.
When once this was accepted it became natural to imagine that they also
were surrounded by planets and to picture each sun as showering life-sus-
taining light and heat on inhabitants more or less like ourselves. In 1829
a New York newspaper scored a great journalistic hit by giving a vivid,
but wholly fictitious, account of the activities of the inhabitants of the
moon as seen through the telescope recently erected by His Majesty's
Government at the Cape.

It would be a long time before we could see what the New York paper
claimed to see on the moon — batlike men flying through the air and
inhabiting houses in trees — even if it were there to see. To see an object
of human size on the moon in detail we should need a telescope of from
10,000 to a 100,000 inches aperture, and even then we should have to wait
years, or more probably centuries, before the air was still and clear enough
for us to see details of human size.

To detect general evidence of life on even the nearest of the planets
would demand far larger telescopes than anything at present in existence,
unless this evidence occupied an appreciable fraction of the planet's surface.
The French astronomer Flammarion once suggested that if chains of light
were placed on the Sahara on a sufficiently generous scale, they might be
visible to Martian astronomers if any such there be. If this light were
placed so as to form a mathematical pattern, intelligent Martians might
conjecture that there was intelligent life on earth. Flammarion thought
that the lights might suitably be arranged to illustrate the theorem of
Pythagoras (Euclid, i. 47). Possibly a better scheme would be a group of
searchlights which could emit successive flashes to represent a series of
numbers. If, for instance, the numbers 3, 5, 7, n, 13, 17, 19, 23 ... (the
sequence of primes) were transmitted, the Martians might surely infer the
existence of intelligent Tellurians. But any visual communication between
planets would need a combination of high telescopic power at one end
and of engineering works on a colossal, although not impossible, scale at
the other.

Some astronomers — mainly in the past — have thought that the so-called
canals on Mars provided evidence of just this kind, although of course
unintentionally on the part of the Martians. Two white patches which
surround the two poles of Mars are observed to increase and decrease with
the seasons, like our terrestrial polar ice. Over the surface of Mars some
astronomers have claimed to see a geometrical network of straight lines,
which they have interpreted as a system of irrigation canals, designed to
bring melted ice from these polar caps to parched equatorial regions.
Percival Lowell calculated that this could be done by a pumping system

IS THERE LIFE ON OTHER WORLDS? 85

of 4,000 times the power of Niagara. It is fairly certain now that the polar
caps are not of ice, but even if they were, the radiation of the summer sun
on Mars is so feeble that it could not melt more than a very thin layer of
ice before the winter cold came to freeze it solid again. Actually the caps
are observed to change very rapidly and are most probably clouds con-
sisting of some kind of solid particles.

The alleged canals cannot be seen at all in the largest telescopes nor
can they be photographed, but there are technical reasons why neither of
these considerations is conclusive against the existence of the canals. A
variety of evidence suggests, however, that the canals are mere subjective
illusions — the result of overstraining the eyes in trying to see every detail
of a never very brightly illuminated surface. Experiments with school chil-
dren have shown that under such circumstances the strained eye tends to
connect patches of color by straight lines. This will at least explain why
various astronomers have claimed to see straight lines not only on Mars,
where it is just conceivable that there might be canals, but also on Mercury
and the largest satellite of Jupiter, where it seems beyond the bounds of
possibility that canals could have been constructed, as well as on Venus, on
which real canals could not possibly be seen since its solid surface is entirely
hidden under clouds. It may be significant that E. E. Barnard, perhaps the
most skilled observer that astronomy has ever known, was never able to
see the canals at all, although he studied Mars for years through the largest
telescopes.

A more promising line of approach to our problem is to examine which,
if any, of the planets is physically suitable for life. But we are at once con-
fronted with the difficulty that we do not know what precise conditions
are necessary for life. A human being transferred to the surface of any
one of the planets or of their satellites, would die at once, and this for
several different reasons on each. On Jupiter he would be simultaneously
frozen, asphyxiated, and poisoned, as well as doubly pressed to death by
his own weight and by an atmospheric pressure of about a million terres-
trial atmospheres. On Mercury he would be burned to death by the sun's
heat, killed by its ultra-violet radiation, asphyxiated from want of oxygen,
and desiccated from want of water. But this does not touch the question
of whether other planets may not have developed species of life suited to
their own physical conditions. When we think of the vast variety of con-
ditions under which terrestrial life exists on earth — plankton, soil bacteria,
stone bacteria, and the great variety of bacteria which are parasitic on the
higher forms of life — it would seem rash to suggest that there are any
physical conditions whatever to which life cannot adapt itself. Yet as the
physical states of other planets are so different from that of our own, it

86 THE HEAVENS

seems safe to say that any life there may be on any of them must be very
different from the life on earth.

The visible surface of Jupiter has a temperature of about — 138° C,
which represents about 248 degrees of frost on the Fahrenheit scale. The
planet probably comprises an inner core of rock, with a surrounding layer
of ice some 16,000 miles in thickness, and an atmosphere which again is
several thousands of miles thick and exerts the pressure of a million
terrestrial atmospheres which we have already mentioned. The only known
constituents of this atmosphere are the poisonous gases methane and
ammonia. It is certainly hard to imagine such a planet providing a home
for life of any kind whatever. The planets Saturn, Uranus, Neptune, and
Pluto, being farther from the sun, are almost certainly even colder than
Jupiter and in all probability suffer from at least equal disabilities as
abodes of life.

Turning sunward from these dismal planets, we come first to Mars,
where we find conditions much more like those of our own planet. The
average temperature is about —40° C., which is also —40° on the Fahren-
heit scale, but the temperature rises above the freezing point on summer
afternoons in the equatorial regions. The atmosphere contains at most
only small amounts of oxygen and carbon dioxide, perhaps none at all, so
that there can be no vegetation comparable with that of the earth. The
surface, in so far as it can be tested by a study of its powers of reflection
and polarization, appears to consist of lava and volcanic ash. To us it may
not seem a promising or comfortable home for life, but life of some kind
or other may be there nevertheless.

Being at the same average distance from the sun as the earth, the moon
has about the same average temperature, but the variations around this
average temperature are enormous, the equatorial temperature varying
roughly from 120° C. to — 80° C. The telescope shows high ranges of
mountains, apparently volcanic, interspersed with flat plains of volcanic
ash. The moon has no atmosphere and consequently no water; it shows
no signs of life or change of any kind, unless perhaps for rare falls of
rock such as might result from the impact of meteors falling in from outer
space. A small town on the moon, perhaps even a large building, ought to
be visible in our largest telescopes, but, needless to say, we see nothing of
the kind.

Venus, the planet next to the earth, presents an interesting problem.
It is similar to the earth in size but being nearer the sun is somewhat
warmer. As it is blanketed in cloud we can only guess as to the nature of
its surface. But its atmosphere can be studied and is found to contain
little or no oxygen, so that the planet's surface can hardly be covered with

IS THERE LIFE ON OTHER WORLDS? 87

vegetation as the surface of the earth is. Indeed, its surface is probably so
hot that water would boil away. Yet no trace of water vapor is found in
the atmosphere, so that the planet may well be devoid of water. There are
reasons for thinking that its shroud of clouds may consist of solid par-
ticles, possibly hydrates of formaldehyde. Clearly any life that this planet
may harbor must be very different from that of the earth.

The only planet that remains is Mercury. This always turns the same
face to the sun and its temperature ranges from about 420° C. at the center
of this face to unimaginable depths of cold in the eternal night of the face
which never sees the sun. The planet is too feeble gravitationally to retain
much of an atmosphere and its surface, in so far as this can be tested,
appears to consist mainly of volcanic ash like the moon and Mars. Once
again we have a planet which does not appear promising as an abode of
life and any life that there may be must be very different from our own.

Thus our survey of the solar system forces us to the conclusion that it
contains no place other than our earth which is at all suitable for life at
all resembling that existing on earth. The other planets are ruled out
largely by unsuitable temperatures. It used to be thought that Mars might
have had a temperature more suited to life in some past epoch when the
sun's radiation was more energetic than it now is, and that similarly
Venus can perhaps look forward to a more temperate climate in some
future age. But these possibilities hardly accord with modern views of
stellar evolution. The sun is now thought to be a comparatively unchanging
structure, which has radiated much as now through the greater part of its
past life and will continue to do the same until it changes cataclysmically
into a minute "white dwarf" star. When this happens there will be a fall
of temperature too rapid for life to survive anywhere in the solar system
and too great for new life ever to get a foothold. As regards suitability for
life, the earth seems permanently to hold a unique position among the
bodies surrounding our sun.

Our sun is, however, only one of myriads of stars in space. Our own
galaxy alone contains about 100,000 million stars, and there are perhaps
10,000 million similar galaxies in space. Stars are about as numerous in
space as grains of sand in the Sahara. What can we say about the possibili-
ties of life on planets surrounding these other suns ?

We want first to know whether these planets exist. Observational astron-
omy can tell us nothing; if every star in the sky were surrounded by a
planetary system like that of our sun, no telescope on earth could reveal a
single one of these planets. Theory can tell us a little more. While there
is some doubt as to the exact manner in which the sun acquired its family
of planets, all modern theories are at one in supposing that it was the

88 THE HEAVENS

result of the close approach of another star. Other stars in the sky must
also experience similar approaches, although calculation shows that such
events must be excessively rare. Under conditions like those which now
prevail in the neighborhood of the sun, a star will experience an approach
close enough to generate planets only about once in every million million
million years. If we suppose the star to have lived under these conditions
for about 2,000 million years, only one star in 500 million will have expe-
rienced the necessary close encounter, so that at most one star in 500
million will be surrounded by planets. This looks an absurdly minute
fraction of the whole, yet when the whole consists of a thousand million
million million stars, this minute fraction represents two million million
stars. On this calculation, then two million million stars must already be
surrounded by planets and a new solar system is born every few hours.
The calculation probably needs many adjustments; for instance, condi-
tions near our sun are not necessarily typical of conditions throughout
space and the conditions of today are probably not typical of conditions in
past ages. Indeed, on any reasonable view of stellar evolution, each star
must have begun its life as a vast mass of nebulous gas, in which state it
would present a far more vulnerable target than now for disruptive attacks
by other stars. Detailed calculation shows that the chance of a star's
producing planets in this early stage, although not large, would be quite
considerable, and suggests, with a large margin to spare, that although
planetary systems may be rare in space, their total number is far from
insignificant. Out of the thousands or millions of millions of planets that
there must surely be in space, a very great number must have physical
conditions very similar to those prevailing on earth.

We cannot even guess whether these are inhabited by life like our own
or by life of any kind whatever. The same chemical atoms exist there as
exist here and must have the same properties, so that it is likely that the
same inorganic compounds have formed there as have formed here. If so,
we would like to know how far the chain of life has progressed, but
present-day science can give no help. We can only wonder whether any
life there may be elsewhere in the universe has succeeded in managing it*
affairs better than we have done in recent years.

1941

The Milky Way ana Beyond

SIR ARTHUR EDDINGTON

IN ONE OF JULES VERNE'S STORIES THE ASTRONOMER
begins his lecture with the words "Gentlemen, you have seen the moon
— or at least heard tell of it." I think I may in the same way presume that
you are acquainted with the Milky Way, which can be seen on any clear
dark night as a faintly luminous band forming an arch from horizon to
horizon. The telescopes show that it is composed of multitudes of stars.
One is tempted to say "countless multitudes"; but it is part of the business
of an astronomer to count them, and the number is not uncountable
though it amounts to more than ten thousand millions. The number
of stars in the Milky Way is considerably greater than the number of
human beings on the earth. Each star, I may remind you, is an immense
fiery globe of the same general nature as our sun.

There is no sharp division between the distant stars which form the
Milky Way and the brighter stars which we see strewn over the sky.
All these stars taken together form one system or galaxy; its extent is
enormous but not unlimited. Since we are situated inside it we do not
obtain a good view of its form; but we are able to see far away in space
other galaxies which also consist of thousands of millions of stars, and
presumably if we could see our own galaxy from outside, it would appear
like one of them. These other galaxies are known as "spiral nebulae."
We believe that our own Milky Way system is more or less like them. If so,
the stars form a flat coil — rather like a watch-spring — except that the coil
is double.

When we look out in directions perpendicular to the plane of the
coil, we soon reach the limit of the system; but in the plane of the coil
we see stars behind stars until they become indistinguishable and fade
into the hazy light of the Milky Way. It has been ascertained that we
are a very long way from the centre of our own galaxy, so that there are
many more stars on one side of us than on the other.

89

90 THE HEAVENS

Looking at one of these galaxies, it is impossible to resist the impression
that it is whirling round— like a Catherine Wheel. It has, in fact, been
possible to prove that some of the spiral nebulae are rotating, and to
measure the rate of rotation. Also by studying the motions of the stars in
our own galaxy, it has been found that it too is rotating about a centre.
The centre is situated a long way from us in the constellation Ophiuchus
near a particularly bright patch of the Milky Way; the actual centre is,
however, hidden from us by a cloud of obscuring matter. My phrase,
"whirling round," may possibly give you a wrong impression. With these
vast systems we have to think in a different scale of space and time, and
the whirling is slow according to our ordinary ideas. It takes about 300
million years for the Milky Way to turn round once. But after all that is
not so very long. Geologists tell us that the older rocks in the earth's
crust were formed 1300 million years ago; so the sun, carrying with it the
earth and planets, has made four or five complete revolutions round the
centre of the galaxy within geological times.

The stars which form our Milky Way system show a very wide diver-
sity. Some give out more than 10,000 times as much light and heat as
the sun; others less than i/iooth. Some are extremely dense and com-
pact; others are extremely tenuous. Some have a surface temperature as
high as 20,000 or 30,000° C.; others not more than 3000° C. Some are
believed to be pulsating — swelling up and deflating within a period of a
few days or weeks; these undergo great changes of light and heat accom-
panying the expansion and collapse. It would be awkward for us if our
sun behaved that way. A considerable proportion (about 1/3 of the whole
number) go about in pairs, forming "double stars"; the majority, how-
ever, are bachelors like the sun.

But in spite of this diversity, the stars have one comparatively uniform
characteristic, namely their mass, that is, the amount of matter which
goes to form them. A range from 1/5 to 5 times the sun's mass would
cover all but the most exceptional stars; and the general run of the masses
is within an even narrower range. Among a hundred stars picked at
random the diversity of mass would not be greater proportionately than
among a hundred men, women and children picked at random from a
crowd.

Broadly speaking, a big star is big, not because it contains an excessive
amount of material, but because it is puffed out like a balloon; and a
small star is small because its material is highly compressed. Our sun,
which is intermediate in this, as in most respects, has a density rather
greater than that of water. (The sun is in every way a typical middle-class
star.) The two extremes—the extremely rarefied and the extremely dense

THE MILKY WAY AND BEYOND 91

stars — are especially interesting. We find stars whose material is as tenuous
as a gas. The well-known star Capella, for example, has an average density
about equal to that of air; to be inside Capella would be like being
surrounded by air, as we ordinarily are, except that the temperature
(which is about 5,000,000° C) is hotter than we are accustomed to. Still
more extreme are the red giant stars Betelgeuse in Orion and Antares in
Scorpio. To obtain a star like Betelgeuse, we must imagine the sun swell-
ing out until it has swallowed up Mercury, Venus and the Earth, and
has a circumference almost equal to the orbit of Mars. The density of
this vast globe is that of a gas in a rather highly exhausted vessel. Betel-
geuse could be described as "a rather good vacuum."

At the other extreme are the "white dwarf stars, which have extrava-
gantly high density. I must say a little about the way in which this was
discovered.

Between 1916 and 1924 I was very much occupied trying to understand
the internal constitution of the stars, for example, finding the temperature
in the deep interior, which is usually ten million degrees, and making out
what sort of properties matter would have at such high temperatures.
Physicists had recently been making great advances in our knowledge of
atoms and radiation; and the problem was to apply this new knowledge
to the study of what was taking place inside a star. In the end I obtained
a formula by which, if you knew the mass of a star, you could calculate
how bright it ought to be. An electrical engineer will tell you that to
produce a certain amount of illumination you must have a dynamo of a
size which he will specify; somewhat analogously I found that for a star
to give a certain amount of illumination it must have a definite mass
which the formula specified. This formula, however, was not intended
to apply to all stars, but only to diffuse stars with densities corresponding
to a gas, because the problem became too complicated if the material
could not be treated as a perfect gas.

Having obtained the theoretical formula, the next thing was to compare
it with observation. That is where the trouble often begins. And there
was trouble in this case; only it was not of the usual kind. The observed
masses and luminosities agreed with the formulae all right; the trouble
was that they would not stop agreeing! The dense stars for which the
formula was not intended agreed just as well as the diffuse stars for
which the formula was intended. This surprising result could only mean
that, although their densities were as great as that of water or iron, the
stellar material was nevertheless behaving like a gas; in particular, it
was compressible like an ordinary gas.

We had been rather blind not to have foreseen this. Why is it that we

92 THE HEAVENS

can compress air, but cannot appreciably compress water? It is because
in air the ultimate particles (the molecules) are wide apart, with plenty
of empty space between them. When we compress air we merely pack
the molecules a bit closer, reducing the amount of vacant space. But in
water the molecules are practically in contact and cannot be packed any
closer. In all substances the ordinary limit of compression is when the
molecules jam in contact; after that we cannot appreciably increase the
density. This limit corresponds approximately to the density of the solid
or liquid state. We had been supposing that the same limit would apply
in the interior of a star. We ought to have remembered that at the temper-
ature of millions of degrees there prevailing the atoms are highly ionized,
i.e. broken up. An atom has a heavy central nucleus surrounded by a
widely extended but insubstantial structure of electrons — a sort of
crinoline. At the high temperature in the stars this crinoline of electrons
is broken up. If you are calculating how many dancers can be accom-
modated in a ball-room, it makes a difference whether the ladies wear
crinolines or not. Judging by the crinolined terrestrial atoms we should
reach the limit of compression at densities not much greater than water;
but the uncrinolined stellar atoms can pack much more densely, and do
not jam together until densities far beyond terrestrial experience are
reached.

This suggested that there might exist stars of density greater than any
material hitherto known, which called to mind a mystery concerning the
Companion of Sirius. The dog-star Sirius has a faint companion close
to it, visible in telescopes of moderate power. There is a method of finding
densities of stars which I must not stop to explain. The method is rather
tentative; and when it was found to give for the Companion of Sirius
a density 50,000 times greater than water, it was naturally assumed that
it had gone wrong in its application. But in the light of the foregoing
discussion, it now seemed possible that the method had not failed, and
that the extravagantly high density might be genuine. So astronomers
endeavoured to check the determination of density by another method
depending on Einstein's relativity theory. The second method confirmed
the high density, and it is now generally accepted. The stuff of the
Companion of Sirius is 2000 times as dense as platinum. Imagine a
match-box filled with this matter. It would need a crane to lift it — it
would weigh a ton.

I am afraid that what I have to say about the stars is largely a matter
of facts and figures. There is only one star near enough for us to study
its surface, namely our sun. Ordinary photographs of the sun show few
features, except the dark spots which appear at times. But much more

THE MILKY WAY AND BEYOND 93

interesting photographs are obtained by using a spectro-heliograph, which
is an instrument blind to all light except that of one particular wave
length — coming from one particular kind of atom.

Now let us turn to the rest of the universe which lies beyond the Milky
Way. Our galaxy is, as it were, an oasis of matter in the desert of empti-
ness, an island in the boundless ocean of space. From our own island we
see in the far distance other islands — in fact a whole archipelago of
islands one beyond another till our vision fails. One of the nearest of
diem can actually be seen with the naked eye; it is in the constellation
Andromeda, and looks like a faint, rather hazy, star. The light which
we now see has taken 900,000 years to reach us. When we look at that
faint object in Andromeda we are looking back 900,000 years into the
past. Some of the telescopic spiral nebulae are much more distant. The
most remote that has yet been examined is 300,000,000 light-years away.

These galaxies are very numerous. From sample counts it is found
that more than a million of them are visible in our largest telescopes; and
there must be many more fainter ones which we do not see. Our sun
is just one star in a system of thousands of millions of stars; and that
whole system is just one galaxy in a universe of thousands of millions
of galaxies.

Let us pause to see where we have now got to in the scale of size. The
following comparative table of distances will help to show us where we
are:

Kilometres

Distance of the sun 150,000,000

Limit of the solar system (Orbit of Pluto) .... 5,800,000,000

Distance of the nearest star 40,000,000,000,000

Distance of nearest external galaxy 8,000,000,000,000,000,000

Distance of furthest galaxy yet observed .... 3,000,000,000,000,000,000,000

Some people complain that they cannot realize these figures. Of course
they cannot. But that is the last thing one wants to do with big numbers —
to "realize" them. In a few weeks time our finance minister in England
will be presenting his annual budget of about ^900,000,000. Do you sup-
pose that by way of preparation, he throws himself into a state of trance in
which he can visualize the vast pile of coins or notes or commodities
that it represents? I am quite sure he cannot "realize" ^900,000,000. But
he can spend it. It is a fallacious idea that these big numbers create a
difficulty in comprehending astronomy; they can only do so if you are
seeking the wrong sort of comprehension. They are not meant to be
gaped at, but to be manipulated and used. It is as easy to use millions

94 THE HEAVENS

and billions and trillions for our counters as ones and twos and threes.
What I want to call attention to in the above table is that since we are
going out beyond the Milky Way we have taken a very big step up in
the scale of distance.

The remarkable thing that has been discovered about these galaxies
is that (except three or four of the nearest of them) they are running
away from our own galaxy; and the further they are away, the faster they
go. The distant ones have very high speeds. On the average the speed
is proportional to the distance, so that a galaxy 10 million light-years
away recedes at 1500 kilometres per second, one 50 million light-years
away recedes at 7500 kilometres per second, and so on. The fastest yet
discovered recedes at 42,000 kilometres per second.

Why are they all running away from us ? If we think a little, we shall
see that the aversion is not especially directed against us; they are running
away from us, but they are also running away from each other. If this
room were to expand 10 per cent in its dimensions, the seats all separating
in proportion, you would at first think that everyone was moving away
from you; the man 10 metres away has moved i metre further off; the
man 20 metres away has moved 2 metres further off; and so on. Just
as with the galaxies, the recession is proportional to the distance. This
law of proportion is characteristic of a uniform expansion, not directed
away from any one centre, but causing a general scattering apart. So we
conclude that recession of the nebulae is an eflect of uniform expansion.

The system of the galaxies is all the universe we know, and indeed
we have strong reason to believe that it is the whole physical universe.
The expansion of the system, or scattering apart of the galaxies, is there-
fore commonly referred to as the expansion of the universe; and the
problem which it raises is the problem of the "expanding universe."

The expansion is proceeding so fast that, at the present rate, the nebulae
will recede to double their present distances in 1300 million years. Astron-
omers will have to double the apertures of their telescopes every 1300
million years in order to keep pace with the recession. But seriously 1300
million years is not a long period of cosmic history; I have already men-
tioned it as the age of terrestrial rocks. It comes as a surprise that the
universe should have doubled its dimensions within geological times.
It means that we cannot go back indefinitely in time; and indeed the
enormous time-scale of billions [The English "billion" is equivalent to
the American "trillion."] of years, which was fashionable ten years ago,
must be drastically cut down. We are becoming reconciled to this speed-
ing up of the time-scale of evolution, for various other lines of evidence
have convinced us that it is essential. It seems clear now that we must

THE MILKY WAY AND BEYOND 95

take an upper limit to the age of the stars not greater than 10,000 million
years; previously, an age of a thousand times longer was commonly
adopted.

For reasons which I cannot discuss fully we believe that along with
the expansion of the material universe there is an expansion of space
itself. The idea is that the island galaxies are scattered throughout a
"spherical space." Spherical space means that if you keep going straight
on in any direction you will ultimately find yourself back at your starting
point. This is analogous to what happens when you travel straight ahead
on the earth; you reach your starting point again, having gone round the
world. But here we apply the analogy to an extra dimension — to space
instead of to a surface. I realize, of course, that this conception of a
closed spherical space is very difficult to grasp, but really it is not worse
than the older conception of infinite open space which no one can properly
imagine. No one can conceive infinity; one just uses the term by habit
without trying to grasp it. If I may refer to our English expression, "out
of the frying-pan into the fire," I suggest that if you feel that in receiving
this modern conception of space you are falling into the fire, please
remember that you are at least escaping from the frying-pan.

Spherical space has many curious properties. I said that if you go
straight ahead in any direction you will return to your starting point. So
if you look far enough in any direction and there is nothing in the way,
you ought to see — the back of your head. Well, not exactly — because
light takes at least 6000 million years to travel round the universe and
your head was not there when it started. But you will understand the
general idea. However, these curiosities do not concern us much. The
main point is that if the galaxies are distributed over the spherical space
more or less in the same way that human beings are distributed over the
earth, they cannot form an expanding system — they cannot all be receding
from one another — unless the space itself expands. So the expansion of
the material system involves, and is an aspect of, an expansion of space.

This scattering apart of the galaxies was not unforeseen. As far back
as 1917, Professor W. de Sitter showed that there was reason to expect
this phenomenon and urged astronomers to look for it. But it is only
recently that radial velocities of spiral nebulae have been measured in
sufficient numbers to show conclusively that the scattering occurs. It is
one of the deductions from relativity theory that there must exist a force,
known as "cosmical repulsion," which tends to produce this kind of
scattering in which every object recedes from every other object. You
know the theory of relativity led to certain astronomical consequences
— a bending of light near the sun detectable at eclipses, a motion of the

96 THE HEAVENS

perihelion of Mercury, a red-shift of spectral lines — which have been
more or less satisfactorily verified. The existence of cosmical repulsion
is an equally definite consequence of the theory, though this is not so
widely known — partly because it comes from a more difficult branch of
the theory and was not noticed so early, and perhaps partly because it is
not so directly associated with the magic name of Einstein.

I can see no reason to doubt that the observed recession of the spiral
nebulae is due to cosmical repulsion, and is the effect predicted by
relativity theory which we were hoping to find. Many other explanations
have been proposed — some of them rather fantastic — and there has been
a great deal of discussion which seems to me rather pointless. In this, as
in other developments of scientific exploration, we must recognize the
limitations of our present knowledge and be prepared to consider revolu-
tionary changes. But when, as in this case, observation agrees with what
our existing knowledge had led us to expect, it is reasonable to feel
encouraged to pursue the line of thought which has proved successful;
and there seems little excuse for an outburst of unsupported speculation.

. , , Now we have been all over the universe. If my survey has been
rather inadequate, I might plead that light takes 6000 million years to
make the circuit that I have made in an hour. Or rather, that was the
original length of the circuit; but the universe is expanding continually,
and whilst I have been talking the increase of the circuit amounts to one
or two more days' journey for the light. Anyhow, the time has come to
leave this nightmare of immensity and find again, among the myriads
of orbs, the tiny planet which is our home.

'957

B. THE EARTH

A Young Man Looking at Rocks

HUGH MILLER

M

From The Old Red Sandstone

rY ADVICE TO YOUNG WORKING MEN DESIROUS OF
bettering their circumstances, and adding to the amount of their
enjoyment, is a very simple one. Do not seek happiness in what is mis-
named pleasure; seek it rather in what is termed study. Keep your con-
sciences clear, your curiosity fresh, and embrace every opportunity of
cultivating your minds. You will gain nothing by attending Chartist
meetings. The fellows who speak nonsense with fluency at these assem-
blies, and deem their nonsense eloquence, are totally unable to help either
you or themselves : or, if they do succeed in helping themselves, it will be
all at your expense. Leave them to harangue unheeded, and set yourselves
to occupy your leisure hours in making yourselves wiser men. Learn to
make a right use of your eyes; the commonest things are worth looking
at — even stones and weeds, and the most familiar animals.

It was twenty years last February since I set out, a little before sunrise
to make my first acquaintance with a life of labour and restraint: and I
have rarely had a heavier heart than on that morning. I was but a slim,
loose-jointed boy at the time, fond of the pretty intangibilities of romance,
and of dreaming when broad awake; and, woeful change! I was now
going to work at what Burns has instanced, in his "Twa Dogs" as one of
the most disagreeable of all employments, — to work in a quarry. Bating
the passing uneasiness occasioned by a few gloomy anticipations, the
portion of my life which had already gone by had been happy beyond the
common lot. I had been a wanderer among rocks and woods, a reader of
curious books when I could get them, a gleaner of old traditionary stories:
and now I was going to exchange all my day-dreams, and all my amuse-

97

98 THE EARTH

ments, for the kind of life in which men toil every day that they may be
enabled to eat, and eat every day that they may be enabled to toil!

The quarry in which I wrought lay on the southern shore of a noble
inland bay, or frith rather, with a little clear stream on the one side,
and a thick fir wood on the other. It had been opened in the Old Red
Sandstone of the district, and was overtopped by a huge bank of diluvial
clay, which rose over it in some places to the height of nearly thirty feet,
and which at this time was rent and shivered, wherever it presented an
open front to the weather, by a recent frost. A heap of loose fragments,
which had fallen from above, blocked up the face of the quarry, and my
first employment was to clear them away. The friction of the shovel
soon blistered my hands, but the pain was by no means very severe, and I
wrought hard and willingly, that I might see how the huge strata below,
which presented so firm and unbroken a frontage, were to be torn up
and removed. Picks, and wedges, and levers, were applied by my
brother- workers; and, simple and rude as I had been accustomed to regard
these implements, I found I had much to learn in the way of using them.
They all proved inefficient, however, and the workmen had to bore into
one of the inferior strata, and employ gunpowder. The process was new
to me, and I deemed it a highly amusing one; it had the merit, too, of
being attended with some such degree of danger as a boating or rock excur-
sion, and had thus an interest independent of its novelty. We had a few
capital shots: the fragments flew in every direction; and an immense
mass of the diluvium came toppling down, bearing with it two dead birds,
that in a recent storm had crept into one of the deeper fissures, to die in
the shelter. I felt a new interest in examining them. The one "was a pretty
cock goldfinch, with its hood of vermilion, and its wings inlaid with the
gold to which it owes its name, as unsoiled and smooth as if it had been
preserved for a museum. The other, a somewhat rarer bird, of the wood-
pecker tribe, was variegated with light blue and a grayish yellow. I was
engaged in admiring the poor little things, more disposed to be senti-
mental, perhaps, than if I had been ten years older, and thinking of the
contrast between the warmth and jollity of their green summer haunts,
and the cold and darkness of their last retreat, when I heard our employer
bidding the workmen lay by their tools. I looked up, and saw the sun
sinking behind the thick fir wood beside us, and the long dark shadows of
the trees stretching downwards towards the shore.

This was no very formidable beginning of the course of life I had so
much dreaded. To be sure, my hanas were a little sore, and I felt nearly
as much fatigued as if I had been climbing among the rocks; but I had
wrought and been useful, and had yet enjoyed the day fully as much as
usual. It was no small matter, too, that the evening, converted, by a rare

A YOUNG MAN LOOKING AT ROCKS 99

transmutation, into the delicious "blink of rest" which Burns so truthfully
describes, was all my own. I was as light of heart next morning as any of
my brother-workmen. There had been a smart frost during the night, and
the rime lay white on the grass as we passed onwards through the fields;
but the sun rose in a clear atmosphere, and the day mellowed, as it
advanced, into one of those delightful days of early spring which give so
pleasing an earnest of whatever is mild and genial in the better half of the
year.

The gunpowder had loosened a large mass in one of the interior strata,
and our first employment, on resuming our labours, was to raise it from
its bed. I assisted the other workmen in placing it on edge, and was much
struck by the appearance of the platform on which it had rested. The
entire surface was ridged and furrowed like a bank of sand that had been
left by the tide an hour before. I could trace every bend and curvature,
every cross hollow and counter ridge, of the corresponding phenomena;
for the resemblance was no half resemblance, — it was the thing itself;
and I had observed it a hundred and a hundred times, when sailing my
little schooner in the shallows left by the ebb. But what had become of the
waves that had thus fretted the solid rock, or of what element had they
been composed ? I felt as completely at fault as Robinson Crusoe did on his
discovering the print of the man's foot on the sand. The evening furnished
me with still further cause of wonder. We raised another block in a
different part of the quarry, and found that the area of a circular depres-
sion in the stratum below was broken and flawed in every direction, as
if it had been the bottom of a pool recently dried up, which had shrunk
and split in the hardening. Several large stones came rolling down from
the diluvium in the course of the afternoon. They were of different
qualities from the sandstone below, and from one another; and, what was
more wonderful still, they were all rounded and water-worn, as if they had
been tossed about in the sea or the bed of a river for hundreds of years.
There could not, surely, be a more conclusive proof that the bank which
had enclosed them so long could not have been created on the rock on
which it rested. No workman ever manufactures a half-worn article, and
the stones were all half -worn! And if not the bank, why then the sand-
stone underneath? I was lost in conjecture, and found I had food enough
for thought that evening, without once thinking of the unhappiness of a
life of labour.

The immense masses of diluvium which we had to clear away rendered
the working of the quarry laborious and expensive, and all the party
quitted it in a few days, to make trial of another that seemed to promise
better. The one we left is situated, as I have said, on the southern shore
of an inland bay, — the Bay of Cromarty; the one to which we removed

100 THE EARTH

has been opened in a lofty wall of cliffs that overhangs the northern
shore of the Moray Frith. I soon found I was to be no loser by the change.
Not the united labours of a thousand men for more than a thousand years
could have furnished a better section of the geology of the district than this
range of cliffs. It may be regarded as a sort of chance dissection on the
earth's crust. We see in one place the primary rock, with its veins of
granite and quartz, its dizzy precipices of gneiss, and its huge masses
o£ horneblend; we find the secondary rock in another, with its beds of
sandstone and shale, its spars, its clays, and its nodular limestones. We
discover the still little-known but highly interesting fossils of the Old
Red Sandstone in one deposition; we find the beautifully preserved shells
and lignites of the Lias in another. There are the remains of two several
creations at once before us. The shore, too, is heaped with rolled fragments
of almost every variety of rock, — basalts, ironstones, hyperstenes, porphy-
ries, bituminous shales, and micaceous schists. In short, the young geologist,
had he all Europe before him could hardly choose for himself a better
field. I had, however, no one to tell me so at the time, for Geology had
not yet travelled so far north; and so, without guide or vocabulary, I had
to grope my way as I best might, and find out all its wonders for myself.
But so slow was the process, and so much was I a seeker in the dark, that
the facts contained in these few sentences were the patient gatherings of
years.

In the course of the first day's employment I picked up a nodular mass
of blue limestone, and laid it open by a stroke of the hammer. Wonder-
ful to relate, it contained inside a beautifully finished piece of sculpture,—
one of the volutes, apparently, of an Ionic capital; and not the far-famed
walnut of the fairy tale, had I broken the shell and found the little dog
lying within, could have surprised me more. Was there another such
curiosity in the whole world ? I broke open a few other nodules of similar
appearance, — for they lay pretty thickly on the shore, — and found that
there might be. In one of these there were what seemed to be the scales
of fishes, and the impressions of a few minute bivalves, prettily striated;
in the centre of another there was actually a piece of decayed wood. Of
all Nature's riddles, these seemed to me to be at once the most interesting
and the most difficult to expound. I treasured them carefully up, and was
told by one of the workmen to whom I showed them, that there was a
part of the shore about two miles farther to the west where curiously-
shaped stones, somewhat like the heads of boarding-pikes, were occasion-
ally picked up; and that in his father's days the country people called
them thunderbolts, and deemed them of sovereign efficacy in curing
bewitched cattle. Our employer, on quitting the quarry for the building or*

A YOUNG MAN LOOKING AT ROCKS 101

which we were to be engaged, gave all the workmen a half-holiday- I
employed it in visiting the place where the thunderbolts had fallen so
thickly, and found it a richer scene of wonder than I could have fancied
in even my dreams.

What first attracted my notice was a detached group of low-lying
skerries, wholly different in form and colour from the sandstone cliffs
above or the primary rocks a little farther to the west. I found them com-
posed of thin strata of limestone, alternating with thicker beds of a black
slaty substance, which, as I ascertained in the course of the evening, burns
with a powerful flame, and emits a strong bituminous odour. The layers
into which the beds readily separate are hardly an eighth part of an inch
in thickness, and yet on every layer there are the impressions of thousands
and tens of thousands of the various fossils peculiar to the Lias. We may
turn over these wonderful leaves one after one, like the leaves of a
herbarium, and find the pictorial records of a former creation in every
page: scallops, and gryphites, and ammonites, of almost every variety
peculiar to the formation, and at least some eight of ten varieties of
belemnite; twigs of wood, leaves of plants, cones of an extinct species of
pine, bits of charcoal, and the scales of fishes; and, as if to render their
pictorial appearance more striking, though the leaves of this interesting
volume are of a deep black, most of the impressions are of a chalky white-
ness. I was lost in admiration and astonishment, and found my very
imagination paralysed by an assemblage of wonders that seemed to out-
rival in the fantastic and the extravagant even its wildest conceptions. I
passed on from ledge to ledge, like the traveller of the tale through the
city of statues, and at length found one of the supposed aerolites I had
come in quest of firmly imbedded in a mass of shale. But I had skill
enough to determine that it was other than what it had been deemed.
A very near relative, who had been a sailor in his time on almost every
ocean, and had visited almost every quarter of the globe, had brought
home one of these meteoric stones with him from the coast of Java. It
was of a cylindrical shape and vitreous texture, and it seemed to have
parted in the middle when in a half-molten state, and to have united
again, somewhat awry, ere it had cooled enough to have lost the adhesive
quality. But there was nothing organic in its structure; whereas the stone
I had now found was organized very curiously indeed. It was of a coni-
cal form and filamentary texture, the filaments radiating in straight lines
from the centre to the circumference. Finely-marked veins like white
threads ran transversely through these in its upper half to the point; while
the space below was occupied by an internal cone, formed of plates that
lay parallel to the base, and which, like watch-glasses, were concave on the

102 THE EARTH

under side and convex on the upper. I learned in time to call this stone
a belemnite, and became acquainted with enough of its history to know
that it once formed part of a variety of cuttle-fish, long since extinct.

My first year of labour came to a close, and I found that the amount
of my happiness had not been less than in the last of my boyhood. My
knowledge, too, had increased in more than the skill of at least the com-
mon mechanic, I had fitted myself for independence. The additional
experience of twenty years has not shown me that there is any necessary
connection between a life of toil and a life of wretchedness; and when I
have found good men anticipating a better and a happier time than
either the present or the past, the conviction that in every period of the
world's history the great bulk of mankind must pass their days in labour,
has not in the least inclined me to scepticism. . . .

One important truth I would fain press on the attention of my low-
lier readers: there are few professions, however humble, that do not pre-
sent their peculiar advantages of observation; there are none, I repeat,
in which the exercise of the faculties does not lead to enjoyment. I
advise the stone-mason, for instance, to acquaint himself with Geology.
Much of his time must be spent amid the rocks and quarries of widely-
separated localities. The bridge or harbour is no sooner completed in one
district than he has to remove to where the gentleman's seat or farm-
steading is to be erected in another; and so, in the course of a few years,
he may pass over the whole geological scale, even when restricted to Scot-
land, from the Grauwacke of the Lammermuirs, to the Wealden of
Moray or the Chalk-flints of Banffshire and Aberdeen; and this, too,
with opportunities of observation at every stage which can be shared with
him by only the gentleman of fortune who devotes his whole time to the
study. Nay, in some respects his advantages are superior to those of the
amateur himself. The latter must often pronounce a formation unfossilif-
erous when, after the examination of at most a few days, he discovers ir
it nothing organic; and it will be found that half the mistakes of geolo-
gists have arisen from conclusions thus hastily formed. But the working
man, whose employments have to be carried on in the same formation for
months, perhaps years, together, enjoys better opportunities for arriving
at just decisions. There are, besides, a thousand varieties of accident which
lead to discovery, — floods, storms, landslips, tides of unusual height, ebbs
of extraordinary fall; and the man who plies his labour at all seasons in
the open air has by much the best chance of profiting by these. There
are formations which yield their organisms slowly to the discoverer, and
the proofs which establish their place in the geological scale more tardily
.still. I was acquainted with the Old Red Sandstone of Ross and Cromarty

GEOLOGICAL CHANGE 103

for nearly ten years ere I had ascertained that it is richly fossiliferous, —
a discovery which, in exploring this formation in those localities, some of
our first geologists had failed to anticipate: I was acquainted with it for
nearly ten years more ere I could assign to its fossils their exact place in
the scale.

. . . Should the working man be encouraged by my modicum of success
to improve his opportunities of observation, I shall have accomplished the
whole of it. It cannot be too extensively known, that nature is vast and
knowledge limited, and that no individual, however humble in place
or acquirement, need despair of adding to the general fund.

1841

Geological Change

SIR ARCHIBALD GEIKE

IT WAS A FUNDAMENTAL DOCTRINE OF HUTTON
[James Hutton, 1726-1797] and his school that this globe has not
always worn the aspect which it bears at present; that on the contrary,
proofs may everywhere be culled that the land which we now see has
been formed out of the wreck of an older land. Among these proofs, the
most obvious are supplied by some of the more' familiar kinds of rocks,
which teach us that, though they are now portions of the dry land, they
were originally sheets of gravel, sand, and mud, which had been worn
from the face of long-vanished continents, and after being spread out
over the floor of the sea were consolidated into compact stone, and
were finally broken up and raised once more to form part of the dry
land. This cycle of change involved two great systems of natural proc-
esses. On the one hand, men were taught that by the action of running
water the materials of the solid land are in a state of continual decay and
transport to the ocean. On the other hand, the ocean floor is liable from
time to time to be upheaved by some stupendous internal force akin

104 THE EARTH

to that which gives rise to the volcano and the earthquake. Hutton
further perceived that not only had the consolidated materials been dis-
rupted and elevated, but that masses of molten rock had been thrust
upward among them, and had cooled and crystallized in large bodies
of granite and other eruptive rocks which form so prominent a feature
on the earth's surface.

It was a special characteristic of this philosophical system that it sought
in the changes now in progress on the earth's surface an explanation of
those which occurred in older times. Its founder refused to invent causes
or modes of operation, for those with which he was familiar seemed to
him adequate to solve the problems with which he attempted to deal.
Nowhere was the profoundness of his insight more astonishing than in
the clear, definite way in which he proclaimed and reiterated his doc-
trine, that every part of the surface of the continents, from mountain
top to seashore, is continually undergoing decay, and is thus slowly
travelling to the sea. He saw that no sooner will the sea floor be elevated
into new land than it must necessarily become a prey to this universal
and unceasing degradation. He perceived that as the transport of dis-
integrated material is carried on chiefly by running water, rivers must
slowly dig out for themselves the channels in which they flow, and thus
that a system of valleys, radiating from the water parting of a country,
must necessarily result from the descent of the streams from the moun-
tain crests to the sea. He discerned that this ceaseless and wide-spread
decay would eventually lead to the entire demolition of the dry land, but
he contended that from time to time this catastrophe is prevented by the
operation of the under-ground forces, whereby new continents are up-
heaved from the bed of the ocean. And thus in his system a due
proportion is maintained between land and water, and the condition of
the earth as a habitable globe is preserved.

A theory of the earth so simple in outline, so bold in conception, so
full of suggestion, and resting on so broad a base of observation and
reflection, ought (we think) to have commanded at once the attention
of men of science, even if it did not immediately awaken the interest
of the outside world; but, as Playfair sorrowfully admitted, it attracted
notice only very slowly, and several years elapsed before any one showed
himself publicly concerned about it, either as an enemy or a friend.
Some of its earliest critics assailed it for what they asserted to be its
irreligious tendency, — an accusation which Hutton repudiated with much
warmth. The sneer levelled by Cowper a few years earlier at all inquiries
into the history of the universe was perfectly natural and intelligible from
that poer's point of view. There was then a wide-spread belief that this

GEOLOGICAL CHANGE 105

world came into existence some six thousand years ago, and that any
attempt greatly to increase that antiquity was meant as a blow to the
authority of Holy Writ. So far, however, from aiming at the overthrow
o£ orthodox beliefs, Hutton evidently regarded his "Theory" as an
important contribution in aid of natural religion. He dwelt with
unfeigned pleasure on the multitude of proofs which he was able to
accumulate of an orderly design in the operations of Nature, decay and
renovation being so nicely balanced as to maintain the habitable con-
dition of the planet. But as he refused to admit the predominance of
violent action in terrestrial changes, and on the contrary contended for
the efficacy of the quiet, continuous processes which we can even now
see at work around us, he was constrained to require an unlimited
duration of past time for the production of those revolutions of which
he perceived such clear and abundant proofs in the crust of the earth.
The general public, however, failed to comprehend that the doctrine of
the high antiquity of the globe was not inconsistent with the com-
paratively recent appearance of man, — a distinction which seems so
obvious now.

Hutton died in 1797, beloved and regretted by the circle of friends
who had learned to appreciate his estimable character and to admire his
genius, but with little recognition from the world at large. Men knew
not then that a great master had passed away from their midst, who
had laid broad and deep the foundations of a new science; that his name
would become a household word in after generations, and that pilgrims
would come from distant lands to visit the scenes from which he drew
his inspiration. . . .

Clear as was the insight and sagacious the inferences of the great
masters [of the Edinburgh school] in regard to the history of the globe,
their vision was necessarily limited by the comparatively narrow range
of ascertained fact which up to their time had been established. They
taught men to recognize that the present world is built of the ruins of
an earlier one, and they explained with admirable perspicacity the oper-
ation of the processes whereby the degradation and renovation of land
are brought about. But they never dreamed that a long and orderly series
of such successive destructions and renewals had taken place and had
left their records in the crust of the earth. They never imagined that
from these records it would be possible to establish a determinate
chronology that could be read everywhere and applied to the elucidation
of the remotest quarter of the globe. It was by the memorable observa-
tions and generalizations of William Smith that this vast extension of
our knowledge of the past history of the earth became possible. While

106 THE EARTH

the Scottish philosophers were building up their theory here, Smith was
quietly ascertaining by extended journeys that the stratified rocks of the
west of England occur in a definite sequence, and that each well-marked
group of them can be discriminated from the others and identified across
the country by means of its inclosed organic remains. It is nearly a hun-
dred years since he made known his views, so that by a curious coin-
cidence we may fitly celebrate on this occasion the centenary of William
Smith as well as that of James Hutton. No single discovery has ever had
a more momentous and far-reaching influence on the progress of a
science than that law of organic succession which Smith established. At
first it served merely to determine the order of the stratified rocks of
England. But it soon proved to possess a world-wide value, for it was
found to furnish the key to the structure of the whole stratified crust
of the earth. It showed that within that crust lie the chronicles of a long
history of plant and animal life upon this planet, it supplied the means
of arranging the materials for this history in true chronological sequence,
and it thus opened out a magnificent vista through a vast series of ages,
each marked by its own distinctive types of organic life, which, in pro-
portion to their antiquity, departed more and more from the aspect of the
living world.

Thus a hundred years ago, by the brilliant theory of Hutton and the
fruitful generalization of Smith, the study of the earth received in our
country the impetus which has given birth to the modern science of
geology. . . .

From the earliest times the natural features of the earth's surface have
arrested the attention of mankind. The rugged mountain, the cleft ravine,
the scarped cliff, the solitary bowlder, have stimulated curiosity and
prompted many a speculation as to their origin. The shells embedded by
millions in the solid rocks of hills far removed from the seas have still
further pressed home these "obstinate questionings." But for many long
centuries the advance of inquiry into such matters was arrested by the
paramount influence of orthodox theology. It was not merely that the
church opposed itself to the simple and obvious interpretation of these
natural phenomena. So implicit had faith become in the accepted views
of the earth's age and of the history of creation, that even laymen of
intelligence and learning set themselves unbidden and in perfect good
faith to explain away the difficulties which nature so persistently raised
up, and to reconcile her teachings with those of the theologians. . . .

It is the special glory of the Edinburgh school of geology to have cast
aside all this fanciful trifling. Hutton boldly proclaimed that it was no
part of his philosophy to account for the beginning of things. His con-

GEOLOGICAL CHANGE 107

cern lay only with the evidence furnished by the earth itself as to its
origin. With the intuition of true genius he early perceived that the only
basis from which to explore what has taken place in bygone time is a
knowledge of what is taking place to-day. He thus founded his system
upon a careful study of the process whereby geological changes are now
brought about. . . .

Fresh life was now breathed into the study of the earth. A new spirit
seemed to animate the advance along every pathway of inquiry. Facts
that had long been familiar came to possess a wider and deeper meaning
when their connection with each other was recognized as parts of one
great harmonious system of continuous change. In no department of
Nature, for example, was this broader vision more remarkably displayed
than in that wherein the circulation of water between land and sea plays
the most conspicuous part. From the earliest times men had watched the
coming of clouds, the fall of rain, the flow of rivers, and had recognized
that on this nicely adjusted machinery the beauty and fertility of the land
depend. But they now learned that this beauty and fertility involve a
continual decay of the terrestrial surface; that the soil is a measure of this
decay, and would cease to afford us maintenance were it not continually
removed and renewed, that through the ceaseless transport of soil by
rivers to the sea the face of the land is slowly lowered in level and carved
into mountain and valley, and that the materials thus borne outwards to
the floor of the ocean are not lost, but accumulate there to form rocks,
which in the end will be upraised into new lands. Decay and renovation,
in well-balanced proportions, were thus shown to be the system on which
the existence of the earth as a habitable globe had been established. It
was impossible to conceive that the economy of the planet could be main-
tained on any other basis. Without the circulation of water the life of
plants and animals would be impossible, and with the circulation the
decay of the surface of the; land and the renovation of its disintegrated
materials are necessarily involved.

As it is now, so must it have been in past time. Hutton and Playfair
pointed to the stratified rocks of the earth's crust as demonstrations that
the same processes which are at work to-day have been in operation from
a remote antiquity. . . .

Obviously, however, human experience, in the few centuries during
which attention has been turned to such subjects, has been too brief to
warrant any dogmatic assumption that the various natural processes
must have been carried on in the past with the same energy and at the
same rate as they are carried on now. ... It was an error to take for
granted that no other kind of process or influence, nor any variation in

108 THE EARTH

the rate of activity save those of which man has had actual cognizance,
has played a part in the terrestrial economy. The uniformitarian writers
laid themselves open to the charge of maintaining a kind of perpetual
motion in the machinery of Nature. They could find in the records of the
earth's history no evidence of a beginning, no prospect of an end. . . .

The discoveries of William Smith, had they been adequately under-
stood, would have been seen to offer a corrective to this rigidly uni-
formitarian conception, for they revealed that the crust of the earth con-
tains the long record of an unmistakable order of progression in organic
types. They proved that plants and animals have varied widely in suc-
cessive periods of the earth's history; the present condition of organic
life being only the latest phase of a long preceding series, each stage of
which recedes further from the existing aspect of things as we trace it
backward into the past. And though no relic had yet been found, or
indeed was ever likely to be found, of the first living things that appeared
upon the earth's surface, the manifest simplification of types in the
older formations pointed irresistibly to some beginning from which the
long procession has taken its start. If then it could thus be demonstrated
that there had been upon the globe an orderly march of living forms
from the lowliest grades in early times to man himself to-day, and thus
that in one department of her domain, extending through the greater
portion of the records of the earth's history, Nature had not been
uniform, but had followed a vast and noble plan of evolution, surely it
might have been expected that those who discovered and made known
this plan would seek to ascertain whether some analogous physical pro-
gression from a definite beginning might not be discernible in the frame-
work of the globe itself.

But the early masters of the science labored under two great disad-
vantages. In the first place, they found the oldest records of the earth's
history so broken up and effaced as to be no longer legible. And in the
second place, . . . they considered themselves bound to search for facts,
not to build up theories; and as in the crust of the earth they could find
no facts which threw any light upon the primeval constitution and sub-
sequent development of our planet, they shut their ears to any theoretical
interpretations that might be offered from other departments of science. . . .

What the more extreme members of the uniformitarian school failed
to perceive was the absence of all evidence that terrestrial catastrophes
even on a colossal scale might not be a part of the present economy of
this globe. Such occurrences might never seriously affect the whole
earth at one time, and might return at such wide intervals that no
example of them has yet been chronicled by man. But that they have

GEOLOGICAL CHANGE 109

occurred again and again, and even within comparatively recent geolog-
ical times, hardly admits of serious doubt. . . .

As the most recent and best known of these great transformations, the
Ice Age stands out conspicuously before us. ... There can not be any
doubt that after man had become a denizen of the earth, a great physical
change came over the Northern hemisphere. The climate, which had
previously been so mild that evergreen trees flourished within ten or
twelve degrees of the North Pole, now became so severe that vast sheets
of snow and ice covered the north of Europe and crept southward beyond
the south coast of Ireland, almost as far as the southern shores of
England, and across the Baltic into France and Germany. This Arctic
transformation was not an episode that lasted merely a few seasons, and
left the land to resume thereafter its ancient aspect. With various suc-
cessive fluctuations it must have endured for many thousands of years.
When it began to disappear it probably faded away as slowly and
imperceptibly as it had advanced, and when it finally vanished it left
Europe and North America profoundly changed in the character alike
of their scenery and of their inhabitants. The rugged rocky contours of
earlier times were ground smooth and polished by the march of the ice
across them, while the lower grounds were buried under wide and thick
sheets of clay, gravel, and sand, left behind by the melting ice. The
varied and abundant flora which had spread so far within the Arctic
circle was driven away into more southern and less ungenial climes.
But most memorable of all was the extirpation of the prominent large
animals which, before the advent of the ice, had roamed over Europe.
The lions, hyenas, wild horses, hippopotamuses, and other creatures
either became entirely extinct or were driven into the Mediterranean
basin and into Africa. In their place came northern forms — the reindeer,
glutton, musk ox, wooly rhinoceros, and mammoth.

Such a marvellous transformation in climate, in scenery, in vegetation
and in inhabitants, within what was after all but a brief portion of
geological time, though it may have involved no sudden or violent con-
vulsion, is surely entitled to rank as a catastrophe in the history of the
globe. It was probably brought about mainly if not entirely by the oper-
ation of forces external to the earth. No similar calamity having befallen
the continents within the time during which man has been recording his
experience, the Ice Age might be cited as a contradiction to the doc-
trine of uniformity. And yet it manifestly arrived as part of the estab-
lished order of Nature. Whether or not we grant that other ice ages
preceded the last great one, we must admit that the conditions under
which it arose, so far as we know them, might conceivably have occurred

110 THE EARTH

before and may occur again. The various agencies called into play by the
extensive refrigeration of the Northern hemisphere were not different from
those with which we are familiar. Snow fell and glaciers crept as they
do to-day. Ice scored and polished rocks exactly as it still does among
the Alps and in Norway. There was nothing abnormal in the phenomena,
save the scale on which they were manifested. And thus, taking a broad
view of the whole subject, we recognize the catastrophe, while at the
same time we see in its progress the operation of those same natural
processes which we know to be integral parts of the machinery whereby
the surface of the earth is continually transformed.

Among the debts which science owes to the Huttonian school, not the
least memorable is the promulgation of the first well-founded con-
ceptions of the high antiquity of the globe. Some six thousand years had
previously been believed to comprise the whole life of the planet, and
indeed of the entire universe. When the curtain was then first raised
that had veiled the history of the earth, and men, looking beyond the
brief span within which they had supposed that history to have been
transacted, beheld the records of a long vista of ages stretching far away
into a dim illimitable past, the prospect vividly impressed their imagina-
tion. Astronomy had made known the immeasurable fields of space; the
new science of geology seemed now to reveal boundless distances of
time. . . .

The universal degradation of the land, so notable a characteristic of
the earth's surface, has been regarded as an extremely slow process.
Though it goes on without ceasing, yet from century to century it seems
to leave hardly any perceptible trace on the landscapes of a country.
Mountains and plains, hills and valleys appear to wear the same familiar
aspect which is indicated in the oldest pages of history. This obvious
slowness in one of the most important departments of geological activity
doubtless contributed in large measure to form and foster a vague belief
in the vastness of the antiquity required for the evolution of the earth.

But, as geologists eventually came to perceive, the rate of degradation
of the land is capable of actual measurement. The amount of material
worn away from the surface of any drainage basin and carried in the
form of mud, sand, or gravel, by the main river into the sea represents
the extent to which that surface has been lowered by waste in any given
period of time. But denudation and deposition must be equivalent to
each other. As much material must be laid down in sedimentary accumu-
lations as has been mechanically removed, so that in measuring the
annual bulk of sediment borne into the sea by a river, we obtain a clue

GEOLOGICAL CHANGE 111

not only to the rate of denudation of the land, but also to the rate at
which the deposition of new sedimentary formations takes place. . . .

But in actual fact the testimony in favor of the slow accumulation and
high antiquity of the geological record is much stronger than might be
inferred from the mere thickness of the stratified formations. These
sedimentary deposits have not been laid down in one unbroken sequence,
but have had their continuity interrupted again and again by upheaval
and depression. So fragmentary are they in some regions that we can
easily demonstrate the length of time represented there by still existing
sedimentary strata to be vastly less than the time indicated by the gaps in
the series.

There is yet a further and impressive body of evidence furnished by
the successive races of plants and animals which have lived upon the
earth and have left their remains sealed up within its rocky crust. No
universal destructions of organic life are chronicled in the stratified rocks.
It is everywhere admitted that, from the remotest times up to the pres-
ent day, there has been an onward march of development, type succeed-
ing type in one long continuous progression. As to the rate of this evolu-
tion precise data are wanting. There is, however, the important negative
argument furnished by the absence of evidence of recognizable specific
variations of organic forms since man began to observe and record. We
know that within human experience a few species have become extinct,
but there is no conclusive proof that a single new species have come into
existence, nor are appreciable variations readily apparent in forms that
live in a wild state. The seeds and plants found with Egyptian mummies,
and the flowers and fruits depicted on Egyptian tombs, are easily identi-
fied with the vegetation of modern Egypt. The embalmed bodies of
animals found in that country show no sensible divergence from the
structure or proportions of the same animals at the present day. The
human races of Northern Africa and Western Asia were already as
distinct when portrayed by the ancient Egyptian artists as they are now,
and they do not seem to have undergone any perceptible change since
then. Thus a lapse of four or five thousand years has not been accom-
panied by any recognizable variation in such forms of plant and animal
life as can be tendered in evidence. Absence of sensible change in these
instances is, of course, no proof that considerable alteration may not have
been accomplished in other forms more exposed to vicissitudes of
climate and other external influences. But it furnishes at least a presump-
tion in favor of the extremely tardy progress of organic variation.

If, however, we extend our vision beyond the narrow range of human
history, and look at the remains of the plants and animals preserved in

112 THE EARTH

those younger formations which, though recent when regarded as parts
of the whole geological record, must be many thousands of years older
than the very oldest of human monuments, we encounter the most
impressive proofs of the persistence of specific forms. Shells which lived
in our seas before the coming of the Ice Age present the very same
peculiarities of form, structure, and ornament which their descendants
still possess. The lapse of so enormous an interval of time has not
sufficed seriously to modify them. So too with the plants and the higher
animals which still survive. Some forms have become extinct, but few
or none which remain display any transitional gradations into new
species. We must admit that such transitions have occurred, that indeed
they have been in progress ever since organized existence began upon
our planet, and are doubtless taking place now. But we can not detect
them on the way, and we feel constrained to believe that their march
must be excessively slow. . . .

If the many thousands of years which have elapsed since the Ice Age
have produced no appreciable modification of surviving plants and
animals, how vast a period must have been required for that marvellous
scheme of organic development which is chronicled in the rocks! . . .

I have reserved for final consideration a branch of the history of the
earth which, while it has become, within the lifetime of the present
generation, one of the most interesting and fascinating departments of
geological inquiry, owed its first impulse to the far-seeing intellects of
Hutton and Playfair. With the penetration of genius these illustrious
teachers perceived that if the broad masses of land and the great chains
of mountains owe their origin to stupendous movements which from
time to time have convulsed the earth, their details of contour must be
mainly due to the eroding power of running water. They recognized
that as the surface of the land is continually worn down, it is essentially
by a process of sculpture that the physiognomy of every country has been
developed, valleys being hollowed out and hills left standing, and that
these inequalities in topographical detail are only varying and local
accidents in the progress of the one great process of the degradation of
the land.

From the broad and guiding outlines of theory thus sketched we
have now advanced amid ever-widening multiplicity of detail into a
fuller and nobler conception of the origin of scenery. The law of evolu-
tion is written as legibly on the landscapes of the earth as on any other
page of the book of Nature. Not only do we recognize that the existing
topography of the continents, instead of being primeval in origin, has
gradually been developed after many precedent mutations, but we are

GEOLOGICAL CHANGE 113

enabled to trace these earlier revolutions in the structure of every hill
and glen. Each mountain chain is thus found to be a memorial of many
successive stages in geographical evolution. Within certain limits land and
sea have changed places again and again. Volcanoes have broken out
and have become extinct in many countries long before the advent of
man. Whole tribes of plants and animals have meanwhile come and
gone, and in leaving their remains behind them as monuments at once
of the slow development of organic types, and of the prolonged vicissi-
tudes of the terrestrial surface, have furnished materials for a chrono-
logical arrangement of the earth's topographical features. Nor is it only
from the organisms of former epochs that broad generalizations may be
drawn regarding revolutions in geography. The living plants and animals
of to-day have been discovered to be eloquent of ancient geographical
features that have long since vanished. In their distribution they tell us
that climates have changed; that islands have been disjoined from con-
tinents; that oceans once united have been divided from each other, or
once separate have now been joined; that some tracts of land have
disappeared, while others for prolonged periods of time have remained
in isolation. The present and the past are thus linked together, not
merely by dead matter, but by the world of living things, into one vast
system of continuous progression.

1892

Earthquakes — What Are They?

THE REVEREND JAMES B. MACELWANE, S.J.

K)UND ABOUT THIS EARTH OF OURS THERE RUN
certain belts in which earthquakes occur more often than in other
parts of the world. Why should this be the case? We read from time to
time of destructive earthquakes in Japan. But many lesser shocks occur there
of which we never hear. In fact, there is an earthquake, large or small,
somewhere in Japan practically every day. Similarly, the Kurile Islands,
the Aleutian Islands, Alaska and the Queen Charlotte Islands are subject
to frequent earth shocks. Continuing around the Pacific circle, we meet
with many earthquakes in California, Mexico, Central America, Vene-
zuela, Colombia, Ecuador, Bolivia, Peru and Chili. And on the other
side of the Pacific Ocean, the earthquake belt continues from Japan
southward through Formosa and the Philippine Deep to New Zealand.
Another somewhat less striking earthquake zone runs from Mexico and
the Antilles through the northern Mediterranean countries and Asia
Minor into the Pamirs, Turkestan, Assam and the Indian Ocean. In other
parts of the earth, destructive earthquakes also occur, but as more or less
isolated phenomena. Examples in this country are the Mississippi Valley
earthquakes of 1811 and of the following year, and the Charleston earth-
quake of 1886.

Now why should destructive earthquakes occur more frequently in
such a zone or belt as the border of the Pacific Ocean? What is an
earthquake? Centuries ago, many people, and even scientific men,
thought that earthquakes were caused by explosions down in the earth;
and there have not been wanting men in our own time who held this
view. Others, like Alexander von Humboldt, thought that earthquakes
were connected with volcanoes; that the earth is a ball of molten lava
covered by a thin shell of rock and that the volcanoes were a sort of
safety valve. As long as the volcanoes are active, they said, the pressure
within the molten lava of the earth is held down, but when the volcanoes

114

EARTHQUAKES—WHAT ARE THEY? 115

cease their activity, thus closing the safety valves, so to speak, the increas-
ing pressure eventually causes a fracture in the earth's crust. Another
theory supposed that the lava occupied passageways in a more or less
solid portion of the earth underneath the crust and that the movement of
lava within these passages caused such pressure as to burst their walls,
thus causing an earthquake.

Quite a different point of view was taken by those who held the theory
that earthquakes occurred within the uppermost crust of the earth. This
crust was supposed to be honeycombed with vast caves. Even the whole
mountain chain of the Alps was thought to be an immense arch built
up over a cavern. When the arch should break, thus allowing the overly-
ing rocks to drop somewhat, we would have an earthquake. In many
cases, those who held this theory believed that the entire roof would
collapse and that earthquakes are generally due to the impact of the
falling mass of rocks on the floor of the cavern.

But it has been shown, since the discovery of the passage of earthquake
waves through the earth and their registration by means of seismographs,
that the outer portion of the earth down to a depth of at least five
elevenths of the earth's radius is not only solid, but, with the exception of
the outer layers, is more than twice as rigid as steel in the laboratory.
It has also been shown that volcanoes are a purely surface phenomenon;
that they have no connection with each other, even when they are but
a few miles apart. Hence it is clear that earthquakes connected with
volcanoes must be of very local character, if they are to be caused by the
movement of lava. This is found to be actually the case. It is also clear
that some other cause must operate in producing earthquakes, since
destructive earthquakes often occur very far from volcanoes. In fact,
some regions where there are frequent earthquakes have no volcanoes
at all.

In the California earthquake of 1906, there occurred a fracture of the
earth's crust which could be followed at the surface for a distance of
more than 150 miles, extending from the Gualala River Valley on the
northern coast of California southeastward through Tomales Bay and
outside the Golden Gate to the old mission of San Juan Bautista. The
rocks on the east side of this fracture moved southeastward relatively to
those on the west side, so that every road, fence or other structure which
had been built across the line of fracture was offset by varying amounts
up to twenty-one feet. A study of this earthquake led scientific men to the
conclusion that the mechanism of the earthquake was an elastic rebound.
It was thought that the rocks in the portion of the earth's crust west of
the fracture had been draped northward until the ultimate strength of

116 THE EARTH

the rocks was reached along this zone of weakness. When the fracture
occurred, the rocks, like bent springs, sprang back to an unstrained
position. But this did not occur in one continuous throw, but in a series
of jerks, each of which set up elastic vibrations in the rocks. These
vibrations traveled out in all directions and constituted the earthquake
proper. The zone of weakness in which the California earthquake
occurred is a valley known as the San Andreas rift. It is usually quite
straight and ignores entirely the physiography of the region, passing
indifferently over lowlands and mountains and extending more than 300
miles beyond the end of the fracture of 1906 until it is lost in the Colorado
desert east of San Bernardino. The entire floor of the valley has been
broken up by earthquakes occurring through the ages into small blocks
and ridges and even into rock flour.

The San Andreas rift is only one of the many features which parallel
the Pacific Coast in California. There are other lesser rifts on which
earthquakes have occurred. Similar to these rifts in some respects are
the ocean deeps, along the walls of which occur some of the world's
most violent earthquakes.

Why do these features parallel the Pacific shore? And why are earth-
quakes associated with them? Both seem to be connected in some way
with the process of mountain-building, for many of the features in this
circum-Pacific belt are geologically recent. Many have thought that
mountain-building in general and the processes going on around the
Pacific in particular are due to a shortening of the earth's crust caused by
gradual cooling of the interior and the consequent shrinkage, but this
is not evident. While the earth is surely losing heat by radiation into
space, it is being heated by physical and chemical processes connected
with radioactivity at such a rate that, unless the radioactive minerals are
confined to the uppermost ten miles or so of the earth's crust, the earth
must be getting hotter instead of cooler, because the amount of heat
generated must exceed that which is conducted to the surface and radiated
away.

Another suggested cause of earthquakes is isostatic compensation. If
we take a column of rock extending downward from the top of a moun-
tain chain to a given level within the earth's crust and compare it with
another column extending to the same level under a plain, the mountain
column will be considerably longer than the other and consequently will
contain more rock. Hence it should weigh more, unless the rocks of which
it is composed are lighter than those under the plain, but geodesists tell
us that the two columns weigh the same. Hence the rocks under the
plain must be the heavier of the two. But even if this is the case, we

EARTHQUAKES— WHAT ARE THEY? 117

should expect the conditions to change; for rain and weather are continu-
ally removing rocks from the tops of the mountains and distributing the
materials of which they are composed over the plain. Nevertheless,
according to the geodesists, the columns continue to weigh the same.
Hence we must conclude that compensation in some form must be taking
place. There must be an inflow of rock into the mountain column and
an outflow from the plain column. But the cold flow of a portion of a
mass of rock must place enormous strain on the surrounding portions.
When the stress reaches the ultimate strength of the rocks, there must be
fracture and a relief of strain, thus causing an earthquake.

It has recently been found that earthquakes occur at considerable depth
in the earth. Hence they can not be caused by purely surface strains.
There are a few earthquakes which seem to have occurred at depths
up to 300 miles. This is far below the depth of compensation of the
geodesists. It is also below the zone of fracture of the geologists, and far
down in what they call the zone of flow. Can an earthquake be generated
by a simple regional flow? We do not know, but it would seem that
sudden release of strain is necessary to cause the vibrations which we
call an earthquake. It may be that a strain is produced and gradually
grows in such a way as to produce planes of shear such as occur when
a column is compressed lengthwise. These planes of maximum shear
usually form an angle of about forty-five degrees with the direction of
the force. Recent investigation into the failure of steel indicates that under
certain conditions it will retain its full strength up to the moment of
failure when the steel becomes as plastic as mud along the planes of
maximum shear. The two portions of the column then glide over each
other on the plastic zone until the strain is relieved, whereupon the steel
within the zone becomes hard and rigid as before. It may be that a
process somewhat similar to this may take place deep down in the earth,
and that the sheared surface may be propagated upwards through the
zone of flow to the zone of fracture and even to the surface of the earth.
In that case, the plastic shear would give way to true fracture near the
surface.

It is only by a careful study, not only of the waves produced by earth-
quakes and of the permanent displacements which occur in them, but of
the actual movement along the planes of fracture, that we shall be able
to discover what an earthquake really is. For the present, we must be
satisfied with knowing that it is an elastic process; that it is usually
destructive only within a very restricted belt, and that it is probably
produced by the sudden release of a regional strain within the crust of
the earth.

Last Days of St. Pierre

FAIRFAX DOWNEY

From Disaster Fighters

THE PLANTER

TJTOW GRACIOUSLY HAD FORTUNE SMILED ON FERNAND

JL JL Clerc. Little past the age of forty, in this year of 1902, he was the
leading planter of the fair island of Martinique. Sugar from his broad
cane fields, molasses, and mellow rum had made him a man of wealth,
a millionaire. All his enterprises prospered.

Were the West Indies, for all their beauty and their bounty, sometimes
powerless to prevent a sense of exile, an ache of homesickness in the
heart of a citizen of the Republic? Then there again fate had been kind
to Fernand Clerc. Elected a member of the Chamber of Deputies, it was
periodically his duty and his pleasure to embark and sail home to attend
its sessions — home to France, to Paris.

Able, respected, good-looking, blessed with a charming wife and
children, M. Clerc found life good indeed. With energy undepleted by
the tropics, he rode through the island visiting his properties. Tall and
thick grew the cane stalks of his plantation at Vive on the slopes of
Mont Pelee. Mont Pelee — Naked Mountain — well named when lava
erupting from its cone had stripped it bare of its verdure. But that was
long ago. Not since 1851 had its subterranean fires flared up and then
but insignificantly. Peaceful now, its crater held the lovely Lake of
Palms, whose wooded shores were a favorite picnic spot for parties from
St. Pierre and Fort-de-France. Who need fear towering Mont Pelee, once
mighty, now mild, an extinct volcano?

Yet this spring M. Clerc and all Martinique received a rude shock.
The mountain was not dead, it seemed. White vapors veiled her sum-
mit, and by May 2nd she had overlaid her green mantle with a gown

118

LAST DAYS OF ST. PIERRE 119

of gray cinders. Pelee muttered and fumed like an angry woman told
her day was long past. Black smoke poured forth, illumined at night by
jets of flame and flashes of lightning. The grayish snow of cinders covered
the countryside, and the milky waters of the Riviere Blanche altered into
a muddy and menacing torrent.

Nor was Pelee uttering only empty threats. On May 5th, M. Clerc at
Vive beheld a cloud rolling from the mountain down the valley. Sparing
his own acres, the cloud and the stream of smoking lava which it masked,
enveloped the Guerin sugar factory, burying its owner, his wife, over-
seer, and twenty-five workmen and domestics.

Dismayed by this tragedy, M. Clerc and many others moved from the
slopes into St. Pierre. The city was crowded, its population of 25,000
swollen to 40,000, and the throngs that filled the market and the cafes
or strolled through the gorgeously luxuriant Jardin des Plantes lent an
air of added animation, of almost hectic gaiety. When M. Clerc professed
alarm at the behavior of Pelee to his friends, he was answered with
shrugs of shoulders. Danger? On the slopes perhaps, but scarcely here in
St. Pierre down by the sea.

Thunderous, scintillant, Mont Pelee staged a magnificent display of
natural fireworks on the night of May 7th. Whites and negroes stared up
at it, fascinated. Some were frightened but more took a child-like joy
in the vivid spectacle. It was as if the old volcano were celebrating the
advent of tomorrow's fete day.

M. Fernand Clerc did not sleep well that night. He breakfasted early
in the household where he and his family were guests and again expressed
his apprehensions to the large group of friends and relatives gathered
at the table. Politely and deferentially — for one does not jeer a personage
and man of proven courage — they heard him out, hiding their scepticism.

The voice of the planter halted in mid-sentence; and he half rose, his
eyes fixed on the barometer. Its needle was actually fluttering!

M. Clerc pushed back his chair abruptly and commanded his carriage
at once. A meaning look to his wife and four children, and they hastened
to make ready. Their hosts and the rest followed them to the door. Nonf
merely none would join their exodus. Au revoir. A demain.

From the balcony of their home, the American Consul, Thomas
Prentis, and his wife waved to the Clerc family driving by. "Stop," the
planter ordered and the carriage pulled up. Best come along, the planter
urged. His American friends thanked him. There was no danger, they
laughed, and waved again to the carriage disappearing in gray dust as
racing hoofs and wheels sped it out of the city of St. Pierre.

120 THE EARTH

THE GOVERNOR

Governor Mouttet, ruling Martinique for the Republic of France,
glared up at rebellious Mont Pelee. This peste of a volcano was deranging
the island. There had been no such crisis since its captures by the English,
who always relinquished it again to France, or the days when the slaves
revolted. A great pity that circumstances beyond his control should dam-
age the prosperous record of his administration, the Governor reflected.

That miserable mountain was disrupting commerce. Its rumblings
drowned out the band concerts in the Savane. Its pyrotechnics distracted
glances which might far better have dwelt admiringly on the proverbial
beauty of the women of Martinique. . . . Now attention was diverted to a
cruder work of Nature, a sputtering volcano. Parbleul It was enough
to scandalize any true Frenchman.

Governor Mouttet sighed and pored over the reports laid before him.
He had appointed a commission to study the eruption and get at the
bottom of I'affaire Pelee, but meanwhile alarm was spreading. People
were fleeing the countryside and thronging into St. Pierre, deserting that
city for Fort-de-France, planning even to leave the island. Steamship
passage was in heavy demand. The Roraima, due May 8th, was booked
solid out of St. Pierre, one said. This would never do. Steps must be
taken to prevent a panic which would scatter fugitives throughout Mar-
tinique or drain a colony of France of its inhabitants.

A detachment of troops was despatched by the Governor to St. Pierre
to preserve order and halt the exodus. His Excellency, no man to send
others where he himself would not venture, followed with Mme. Mouttet
and took up residence in that city. Certainly his presence must serve to
calm these unreasoning, exaggerated fears. He circulated among the
populace, speaking soothing words. Mes enfants, the Governor avowed,
Mont Pelee rumbling away there is only snoring soundly in deep slum-
ber. Be tranquil.

Yet, on the ominous night of May 7th, as spurts of flame painted the
heavens, the Governor privately confessed to inward qualms. What if
the mountain should really rouse? Might it not then cast the mortals at
its feet into a sleep deeper than its own had been, a sleep from which
they would never awaken?

THE CHIEF OFFICER

Ellery S. Scott, chief officer of the Quebec Line steamship Roraima,
stood on the bridge with Captain Muggah as the vessel bore down on
Martinique. A column of smoke over the horizon traced down to the

LAST DAYS OF ST. PIERRE 121

4,500-foot summit of Mont Pelee. So the old volcano was acting up!
Curiosity on the bridge ran high as anchor was dropped in the St. Pierre
roadstead about 6 o'clock on the morning of May 8th. But all seemed well
ashore. The streets, twisting and climbing between the bright-colored
houses, were filled with crowds in gay holiday attire.

Promptly the agents came aboard. The volcano? But certainly it was
erupting and causing inconvenience. But there was no danger, regardless
of the opinion of that Italian skipper yesterday who had said that had
he seen Vesuvius looking like Pelee, he would have departed from
Naples as fast as he was going to leave St. Pierre. Although the authorities
refused him clearance and threatened penalties, he had sailed in haste,
with only half his cargo.

By the way, the agents continued, the passenger list was to be consid-
erably augmented: sixty first-class anxious to leave St. Pierre. Here they
were boarding now with bag and baggage. Could they be humored, and
the Roraima sail for St. Lucia at once, returning to discharge its Mar-
tinique cargo? the agents inquired of Captain Muggah.

Chief Officer Scott, ordered below to inspect the stowage, thought of
his boy in the forecastle. A good lad this eldest son of his. Used to say
he'd have a ship of his own some day and keep on his father as first mate.
No, his father planned a better career than the sea for him. The boy was
slated to go to college and be a lawyer. This would be his last voyage.

Stowed shipshape and proper as Scott knew he would find it, the
cargo plainly could not be shifted without a good deal of difficulty. The
Martinique consignment lay above that for St. Lucia, and it would be
a heavy task to discharge at the latter port first. Scott so reported.

The agents hesitated briefly. To be sure, sixty first-class passengers were
to be obliged if possible but — ah, well, let them wait a little longer. The
Roraima would sail as soon as the upper layer of cargo was landed.

Ship's bells tolled the passing hours. Pelee yonder growled hoarsely and
belched black smoke. A little before 8, Chief Officer Scott apprehensively
turned his binoculars on the summit.

THE PRISONER

It was dark in the underground dungeon of the St. Pierre prison, but
thin rays of light filtered through the grated opening in the upper part
of the cell door. Enough so that Auguste Ciparis could tell when it was
night and when it was day.

Not that it mattered much unless a man desired to count the days
until he should be free. What good was that ? One could not hurry them
by. Therefore Auguste stolidly endured them with the long patience

122 THE EARTH

of Africa. The judge had declared him a criminal and caused him to
be locked up here. Thus it was settled and nothing was to be done. Yet
it was hard, this being shut out of life up there in the gay city — hard
when one was only twenty-five and strong and lusty.

Auguste slept and dozed all he could. Pelee was rumbling away in the
distance — each day the jailer bringing him food and water seemed more
excited about it — but the noise, reaching the subterranean cell only as
faint thunder, failed to keep the negro awake. . . .

Glimmerings of the dawn of May 8th filtered through the grating into
the cell, and Auguste stirred into wakefulness. This being a fete day,
imprisonment was less tolerable. What merriment his friends would be
making up there in the squares of St. Pierre! He could imagine the side-
long glances and the swaying hips of the mulatto girls he might have
been meeting today. Auguste stared sullenly at the cell door. At least the
jailer might have been on time with his breakfast.

The patch of light in the grating winked out into blackness. Ail Ait
All of a sudden it was night again.

On the morning of May 8th, 1902, the clocks of St. Pierre ticked on
toward ten minutes of 8 when they would stop forever. Against a back-
ground of bright sunshine, a huge column of vapor rose from the cone of
Mont Pelee.

A salvo of reports as from heavy artillery. Then, choked by lava boiled
to white heat by fires in the depths of the earth, Pelee with a terrific
explosion blew its head off.

Like a colossal Roman candle it shot out streaks of flame and fiery
globes. A pall of black smoke rose thousands of feet in the air, darkening
the heavens. Silhouetted by a red, infernal glare, Pelee flung aloft viscid
masses which rained incandescent ashes on land and sea.

Then, jagged and brilliant as the lightning flashes, a fissure opened in
the flank of the mountain toward St. Pierre. Out of it issued an immense
cloud which rushed with unbelievable rapidity down on the doomed city
and the villages of Carbet and Le Precheur.

In three minutes that searing, suffocating cloud enveloped them, and
40,000 people died!

Fernand Clerc, the planter, watched from Mont Parnasse, one mile
east of St. Pierre, where he had so recently breakfasted. Shrouded in such
darkness as only the inmost depths of a cavern afford, he reached out
for the wife and children he could not see and gathered them in blessed
safety into his arms. But the relatives, the many friends he had left s&

LAST DAYS OF ST. PIERRE 123

short a while ago, the American consul and his wife, who had waved him
a gay good-by — them he would never see alive again. . . .

In that vast brazier which was St. Pierre, Governor Mouttet may have
lived the instant long enough to realize that Pelee had in truth awakened
and that eternal sleep was his lot and his wife's and that of all those
whose flight he had discouraged. . . .

Down in that deep dungeon cell of his Auguste Ciparis blinked in the
swift-fallen night. Through the grating blew a current of burning air,
scorching his flesh. He leaped, writhing in agony and screaming for help.
No one answered.

Leaving a blazing city in its wake, the death cloud from the volcano
rolled over the docks, and the sea, hissing and seething, shrank back
before it. Aboard the Roraima, Chief Officer Scott lowered his glasses
precipitately from Pelee. One look at that cloud bearing down like a
whirlwind and he snatched a tarpaulin from a ventilator and pulled it
over him. The ship rolled to port, almost on her beam ends, then back
to starboard. Her funnels and other superstructure and most of her small
boats were swept off by the mighty blast laden with scalding ashes and
stone dust. Badly scorched, Scott emerged from his refuge to catch a
glimpse of the British steamer Roddam plunging by toward the open sea,
her decks a smoking shambles. Of the other sixteen vessels which had
been anchored in the roadstead there was no sign.

Staggering toward the twisted iron wreckage of the bridge, the Chief
Officer beheld the swaying figure of Captain Muggah. From the hideous,
blackened mask that had been his face a voice croaked:

"All hands! Heave up the anchor!"

All hands! Only Scott, two engineers, and a few members of the black
gang who had been below responded. In vain Scott scanned the group for
his son. He never saw the lad again.

The anchor could not be unshackled. "Save the women and children,"
the captain ordered. During attempts to lower a boat, the captain disap-
peared. Later he was pulled out of the water in a dying condition.

Now the Roraima was afire fore and aft. Amid the shrieks and groans
of dying passengers, Scott and three more able-bodied men fought the
flames, helped by a few others whose hands, burned raw, made it torture
to touch anything. Between dousing the fire with bucketfuls from the
sea, Scott tried to give drinks of fresh water to those who begged pitifully
for it, though their seared, swollen throats would not let them swallow a
drop. Tongues lolling, they dragged themselves along the deck, following
him like dogs.

When the French cruiser Suchct steamed up to the rescue, the only

124 THE EARTH

survivors among the passengers were a little girl and her nurse. Twenty-
eight out of a crew of forty-seven were dead.

The eyes of all aboard the Suchet turned toward shore. There at the
foot of a broad, bare pathway, paved by death and destruction down the
slope of Mont Pelee, lay the utter ruins of the city of St. Pierre.

in

Not until the afternoon of May 8th did the devastation of St. Pierre
cool sufficiently to allow rescuers from Fort-de-France to enter. They
could find none to rescue except one woman who died soon after she
was taken from a cellar.

"St. Pierre, that city this morning alive, full of human souls, is no
morel" Vicar-General Parel wrote his Bishop. "It lies consumed before
us, in its windingsheet of smoke and cinders, silent and desolate, a city
of the dead. We strain our eyes for fleeing inhabitants, for men return-
ing to bury their lost ones. We see no one! There is no living being left
in this desert of desolation, framed in a terrifying solitude. In the back-
ground, when the cloud of smoke and cinders breaks away, the moun-
tain and its slopes, once so green, stand forth like an Alpine landscape.
They look as if they were covered with a heavy cloak of snow, and
through the thickened atmosphere rays of pale sunshine, wan, and
unknown to our latitudes, illumine this scene with a light that seems
to belong to the other side of the grave."

Indeed St. Pierre might have been an ancient town, destroyed in
some half-forgotten cataclysm and recently partly excavated— another
Pompeii and Herculaneum. Cinders, which had buried its streets six
feet deep in a few minutes, were as the dust of centuries. Here was the
same swift extinction Vesuvius had wrought.

Here was no slow flow of lava. That cloud disgorged by Pelee was a
superheated hurricane issuing from the depths of the earth at a speed
of ninety miles an hour. Such was the strength of the blast, it killed
by concussion and by toppling walls on its victims. The fall of the
fourteen-foot metal statue of Notre Dame de la Garde— Our Lady of
Safety— symbolized the dreadful fact that tens of thousands never had a
fighting chance for their lives.

But chiefly the death cloud slew with its lethal content of hot steam
and dust. So swiftly did it pass that its heat did not always burn all of
the light tropical clothing from its prey, but once it was inhaled into
the lungs— that was the end. Some had run a few frantic steps; then
dropped, hands clutched over nose and mouth. Encrusted by cement-
like ashes, corpses lay fixed in the contorted postures of their last struggle

LAST DAYS OF ST. PIERRE 125

replicas of the dead of Vesuvius preserved in the Naples museum. Fire
had charred others or incinerated them to a heap of bones. A horrible
spectacle was presented by bodies whose skulls and abdomens had been
burst by heat and gases.

People who had been indoors when the cloud descended perished
where they stood or sat, but the hand of death had marked most of them
less cruelly. They seemed almost still alive, as each shattered building
disclosed its denouement. There a girl lay prone, her arms about the
feet of an image of the Virgin. A man bent with his head thrust into
a basin from which the water had evaporated. A family was gathered
around a restaurant table. A child held a doll in her arms; when the
doll was touched, it crumbled away except for its china eyes. A clerk
sat at his desk, one hand supporting his chin, the other grasping a pen.
A baker crouched in the fire pit under his oven. In one room of a
home a blonde girl in her bathrobe leaned back in a rocking-chair.
Behind her stood a negro servant who apparently had been combing the
girl's hair. Another servant had crawled under a sofa. Not far away
lay the body of a white woman, beautiful as a Greek statue, and — like
many an antique statue — headless.

Mutilated or almost unmarred, shriveled in last agony or seeming only
to have dropped into a peaceful sleep, lay the legions of the dead. After
the finding of the dying woman in a cellar, the devastation was searched
in vain for survivors.

Then four days after the catastrophe, two negroes walking through the
wreckage turned gray as they heard faint cries for help issuing from the
depths of the earth.

"Who's that?" they shouted when they could speak. " Where are you?"

Up floated the feeble voice: "I'm down here in the dungeon of the jail.
Help! Save me! Get me out!"

They dug down through the debris, broke open the dungeon door,
and released Auguste Ciparis, the negro criminal.

Some days later, George Kennan and August F. Jaccaci, American
journalists arriving to cover the disaster, located Ciparis in a village in the
country. They secured medical attention for his severe burns, poorly
cared for as yet, and obtained and authenticated his story. When the
scorching air penetrated his cell that day, he smelled his own body burn-
ing but breathed as little as possible during the moment the intense heat
lasted. Ignorant of what had occurred, not realizing that he was buried
alive, he slowly starved for four days in his tomb of a cell. His scant
supply of water was soon gone. Only echoes answered his shouts for

126 THE EARTH

help. When at last he was heard and freed, Ciparis, given a drink of water,
managed with some assistance to walk six kilometers to Morne Rouge.

One who lived where 40,000 died! History records no escape more
marvelous.

1938

Man, Maker of Wilderness

PAUL B. SEARS

From Deserts on the March

HPHE FACE OF EARTH IS A GRAVEYARD, AND SO IT HAS

-*L always been. To earth each living thing restores when it dies that
which has been borrowed to give form and substance to its brief day in
the sun. From earth, in due course, each new living being receives back
again a loan of that which sustains life. What is lent by earth has been used
by countless generations of plants and animals now dead and will be
required by countless others in the future. In the case of an element such
as phosphorus, so limited is the supply that if it were not constantly being
returned to the soil, a single century would be sufficient to produce a
disastrous reduction in the amount of life. No plant or animal, nor any
sort of either, can establish permanent right of possession to the materials
which compose its physical body.

Left to herself, nature manages these loans and redemptions in not
unkindly fashion. She maintains a balance which will permit the briefest
time to elapse between burial and renewal. The turnover of material for
new generations to use is steady and regular. Wind and water, those twin
sextons, do their work as gently as may be. Each type of plant and animal,
so far as it is fit, has its segment of activity and can bring forth its own kind
to the limits of subsistence. The red rule of tooth and claw is less harsh
in fact than in seeming. There is a balance in undisturbed nature between

MAN, MAKER OF WILDERNESS 127

food and feeder, hunter and prey, so that the resources of the earth are
never idle. Some plants or animals may seem to dominate the rest, but
they do so only so long as the general balance is maintained. The whole
world of living things exists as a series of communities whose order and
permanence put to shame all but the most successful of human enterprises.

It is into such an ordered world of nature that primitive man fits as a
part. A family of savage man, living by the chase and gathering wild
plants, requires a space of ten to fifty square miles for subsistence. If
neighbors press too closely, the tomahawk of tribal warfare offers a rude
but perhaps merciful substitute for starvation. Man in such a stage takes
what he can get on fairly even terms with the rest of nature. Wind and
water may strike fear to his heart and even wreak disaster upon him, but
on the whole their violence is tempered. The forces of nature expend
themselves beneficently upon the highly developed and well balanced
forests, grasslands, even desert. To the greatest possible extent the surface
consists of mellow, absorbent soil, anchored and protected by living plants
— a system buffered against the caprice of the elements, although of course
subject to slow and orderly change. Bare ground left by the plow will
have as much soil washed off in ten years as the unbroken prairie will lose
in four thousand. Even so, soil in the prairie will be forming as fast as,
or faster than it is lost.

Living in such a setting, man knows little or nothing of nature's laws,
yet conforms to them with the perfection over which he has no more choice
than the oaks and palms, the cats and reptiles around him. Gradually,
however, and with many halting steps, man has learned enough
about the immutable laws of cause and effect so that with tools,
domestic animals, and crops he can speed up the processes of nature
tremendously along certain lines. The rich Nile Valley can be made to sup-
port, not one, but one thousand people per square mile, as it does today.
Cultures develop, cities and commerce flourish, hunger and fear dwindle
as progress and the conquest of nature expand. Unhappily, nature is not
so easily thwarted. The old problems of population pressure and tribal
warfare appear in newer and more horrible guise, with whole nations
trained for slaughter. And back of it all lies the fact that man has upset
the balance under which wind and water were beneficial agents of con-
struction, to release them as twin demons which carve the soil from
beneath his feet, to hasten the decay and burial of his handiwork.

Nature is not to be conquered save on her own terms. She is not con-
ciliated by cleverness or industry in devising means to defeat the operation
of one of her laws through the workings of another. She is a very busi-
ness-like old lady, who plays no favorites. Man is welcome to outnumber

128 THE EARTH

and dominate the other forms of life, provided he can maintain order
among the relentless forces whose balanced operation he has disturbed.
But this hard condition is one which, to date, he has scarcely met. His own
past is full of clear and somber warnings — vanished civilizations like dead
flies in lacquer, buried beneath their own dust and mud.

For man, who fancies himself the conqueror of it, is at once the maker
and the victim of the wilderness. Even the dense and hostile jungles
of the tropics are often the work of his hands. The virgin forest of the
tropics, as of other climes, is no thicket of scrub and thorn, but a cathe-
dral of massive, well-spaced giant trees under whose dense canopy the
alien and tangled rabble of the jungle does not thrive. Order and per-
manence are here — these giants bring forth young after their own kind,
but only so fast as death and decay break the solid ranks of the elders.
Let man clear these virgin forests, even convert them into fields, he can
scarcely keep them. Nature claims them again, and her advance guards
are the scrambled barriers through which man must chop his way.

In the early centuries of the present era, while the Roman Empire was
cracking to pieces, the Mayas built great cities in Central America. Their
huge pyramids, massive masonry, and elaborate carving are proof of capac-
ity and leisure. They also indicate that the people who built them prob-
ably felt a sense of security, permanence, and accomplishment as solid as
our own. To them the end of their world was no doubt unthinkable save
as a device of priestly dialectic, or an exercise of the romantic imagination.
Food there was in abundance, furnished by the maize, cacao, beans,
and a host of other plants of which southern Mexico is the first home.
Fields were easily cleared by girdling trees with sharp stone hatchets. You
can write your name on plate glass with their little jadeite chisels. The
dead trees were then, as they are today in Yucatan, destroyed by fire,
and crops were planted in their ashes.

Yet by the sixth century all of this was abandoned and the Second
Empire established northward in Yucatan, to last with varying fortunes
until the Spanish conquest. Pyramids and stonework became the play-
ground of the jungle, so hidden and bound beneath its knotted mesh
that painful labor has been required to reveal what is below. Farther
north in Yucatan, in humble villages, are the modern people, unable to
read the hieroglyphs of their ancestors, and treasuring only fragments of
the ancient lore which have survived by word of mouth. There persists
among these people, for example, a considerable body of knowledge con-
cerning medicinal plants, their properties and mode of use. But the power
and glory of the cities is gone. In their place are only ruins and wilderness.

MAN, MAKER OF WILDERNESS 129

Their world, once so certain, stable, dependable, and definite, is gone.
And why?

Here of course, is a first-rate mystery for modern skill and knowledge
to unravel. The people were not exterminated, nor their cities taken over
by an enemy. Plagues may cause temporary migrations, but not the perma-
nent abandonment of established and prosperous centers. The present
population to the north has its share of debilitating infections, but its
ancestors were not too weak or wasted to establish the Second Empire
after they left the First. Did the climate in the abandoned cities become so
much more humid that the invasion of dense tropical vegetation could not
be arrested, while fungous pests, insects, and diseases took increasing toll ?
This is hard to prove. Were the inhabitants starved out because they had
no steel tools or draft animals to break the heavy sod which formed over
their resting fields? Many experts think so.

Certainly the soil of the wet tropics is very different from the deep rich
black soil of the prairies. Just as soaking removes salt from a dried
mackerel, so the nourishing minerals are quickly removed from these soils
by the abundant water. In the steaming hot climate the plant and animal
materials which fall upon the ground are quickly rotted, sending gases
into the air and losing much of what is left, in the pounding, soaking wash
of the heavy tropical rains. Such organic material as may be present is
well incinerated when the forest covering is killed and burned, as it was
by the ancient Mayas, and still is by their descendants. Such a clearing will
yield a heavy crop for a few seasons, by virtue of the fertilizer in the ashes
and what little is left in the soil. Presently the yield must decline to the
point where cultivation is no longer possible. A fresh clearing is made
and the old one abandoned. Step by step the cultivation proceeds farther
from the place of beginning. Whether the idle fields, forming an ever
widening border about the great cities, came to be hidden beneath an
armor of impenetrable turf or completely ruined by sheet erosion and
puddling, is immaterial. The restoration of fertility by idleness has proved
a failure even in temperate climates. It is not a matter of one, or even
several, human generations, but a process of centuries. The cities of the
Mayas were doomed by the very system that gave them birth. Man's con-
quest of nature was an illusion, however brilliant. Like China before the
Manchu invaders, or Russia in the face of Napoleon, the jungle seemed to
yield and recede before the Mayas, only to turn with deadly, relentless
deliberation and strangle them.

So much for a striking case of failure in the New World. How about
the Old— the cradle of humanity? Here there are striking cases of apparent
success, long continued, such as eastern China and the Nile Valley. On

130 THE EARTH

the other hand are many instances of self-destruction as dramatic as that
of the Mayas — for example the buried cities of the Sumerian desert. Let
us examine both failure and seeming success; after we have done so, we
shall realize how closely they are interwoven.

The invention of flocks and herds of domestic animals enable man to
increase and prevail throughout the great grassy and even the desert
interior of the Old World. Food and wealth could be moved on the hoof.
A rough and ready "cowpuncher" psychology was developed as a matter
of course, combining a certain ruthless capacity for quick action along with
an aversion to sustained and methodical labor, except for women. Living
as these people did, in a region where water was none too abundant and
pasture not always uniform, movement was necessary. Normally this was
a seasonal migration — a round trip like that of the buffalo and other wild
grazing animals. But from time to time the combination of events brought
about complete and extensive shifts.

Where moisture was more abundant, either directly from rain, or
indirectly through huge rivers, another invention took place. This second
invention was the cultivation of certain nutritious grasses with unusually
large fruits — the cereals. Probably not far from the mouth of the Yangtze
River in southeastern China rice was domesticated, while at the eastern
end of the Mediterranean wheat and barley were put to similar use, both
in Irak (Mesopotamia) and Egypt. Along with these cereals many other
plants, such as beans, clover, alfalfa, onions, and the like were grown.
This invention provided food cheaply and on a hitherto unprecedented
scale. Domestic animals could now be penned, using their energy to make
flesh and milk instead of running it off in the continued movements for
grass and water. Other animals like the cat and dog relieved man of the
necessity of guarding his stored wealth against the raids of rats and
robbers. Large animals like the ox and ass saved him the labor of carriage
and helped in threshing and tillage. The people themselves became
accustomed to methodical and prolonged labor. They devised means of
storage and transport and developed commerce. Mechanical contrivances
proved useful and were encouraged. On the other hand such folk were not
celebrated for their aggressiveness nor for an itching foot. As they became
organized and accumulated a surplus of skill and energy they developed
great cities and other public works, with all adornments.

The history of early civilization can be written largely in terms of
these two great inventions in living — the pastoral life of the dry interior
and the settled agriculture of the well-watered regions. Their commerce,
warfare, and eventual, if imperfect, combination make the Western
Europe of today. What of their effects upon the land?

MAN, MAKER OF WILDERNESS 131

Wherever we turn, to Asia, Europe, or Africa, we shall find the same
story repeated with an almost mechanical regularity. The net productive-
ness of the land has been decreased. Fertility has been consumed and soil
destroyed at a rate far in excess of the capacity of either man or nature to
replace. The glorious achievements of civilization have been builded on
borrowed capital to a scale undreamed by the most extravagant of mon-
archs. And unlike the bonds which statesmen so blithely issue to — and
against — their own people, an obligation has piled up which cannot be
repudiated by the stroke of any man's pen.

Uniformly the nomads of the interior have crowded their great ranges
to the limit. The fields may look as green as ever, until the inevitable drier
years come along. The soil becomes exposed, to be blown away by wind,
or washed into great flooded rivers during the infrequent, usually tor-
rential rains. The cycle of erosion gains momentum, at times conveying
wealth to the farmer downstream in the form of rich black soil, but quite
as often destroying and burying his means of livelihood beneath a coat
of sterile mud.

The reduction of pasture, even with the return of better years, dislocates
the scheme of things for the owners of flocks and herds. Raids, mass migra-
tions, discouraged and feeble attempts at agriculture, or, rarely, the
development of irrigation and dry farming result — and history is made.

Meanwhile, in the more densely settled regions of cereal farming, popu-
lation pressure demands every resource to maintain yield. So long as rich
mud is brought downstream in thin layers at regular intervals, the
valleys yield good returns at the expense of the continental interior. But
such imperial gifts are hard to control, increasingly so as occupation and
overgrazing upstream develop. In the course of events farming spreads
from the valley to the upland. The forests of the upland are stripped,
both for their own product and for the sake of the ground which they
occupy. Growing cities need lumber, as well as food. For a time these
upland forest soils of the moister regions yield good crops, but gradually
they too are exhausted. Imperceptibly sheet erosion moves them into the
valleys, with only temporary value to the latter. Soon the rich black valley
soil is overlain by pale and unproductive material from the uplands. The
latter may become an abandoned range of gullies, or in rarer cases human
resourcefulness may come to the fore, and by costly engineering works
combined with agronomic skill, defer the final tragedy of abandonment.

Thus have we sketched, in broad strokes to be sure, the story of man's
destruction upon the face of his own Mother Earth. The story on the older
continents has been a matter of millennia. In North America it has been
a matter of not more than three centuries at most — generally a matter

132 THE EARTH

of decades. Mechanical invention plus exuberant vitality have accomplished
the conquest of a continent with unparalleled speed, but in doing so have
broken the gentle grip wherein nature holds and controls the forces
which serve when restrained, destroy when unleashed.

*935

What Makes the Weather

THE SEVEN AMERICAN AIRS
WOLFGANG LANGEWIESCHE

WAKE UP ONE MORNING AND YOU ARE SURPRISED:
-"- the weather, which had been gray and dreary for days and seemed
as if it were going to stay that way forever, with no breaks in the clouds
and no indication of a gradual clearing, is now all of a sudden clear and
sunny and crisp, with a strong northwest wind blowing, and the whole
world looks newly washed and newly painted.

"It" has become "fine." Why? How?

"Something" has cleared the air, you might say. But what? You might
study out the weather news in the back of your newspaper, and you would
get it explained to you in terms of barometric highs and lows; but just
why a rise of barometric pressure should clear the air would still leave you
puzzled. The honest truth is that the weather has never been explained.
In school they told you about steam engines or electricity or even about
really mysterious things, such as gravitation, and they could do it so
that it made sense to a boy. They told you also about the weather, but
their explanations failed to explain, and you knew it even then. The lows
and highs, cyclones and anti-cyclones, the winds that blew around in circles
— all these things were much more puzzling than the weather itself. That
is why weather has always made only the dullest conversation: there
simply was no rhyme nor reason to it.

But now there is. A revolutionary fresh view has uncovered the rhyme

WHAT MAKES THE WEATHER 133

and reason in the weather. Applied to your particular surprise of that
morning, it has this to say:

Thejiir^vhkh^^ is .still warm^ moist,

and gray this morning ;, but it Jias been pushed fifty or one hundred
to the south and east of where_^pujiyea _and has been replaced by aj
of "cold, clear, dry air coming from the north or west. It is as simple as that;
there is no mysterious "It" in it; just plain physical sense. It is called Air
Mass Analysis.

It is based upon the researches and experiments of a. physicist named
YilhdlII_Bigrkncs, of_Nprway, and though in this particular case it
seems almostT childishly simple, it is Norway's greatest contribution to
world culture since Ibsen. Or perhaps because it is simple — the rare
example of a science which in becoming more sophisticated also becomes
more common sense and easier to understand. It is so new that it hasn't
yet reached the newspapers, nor the high school curricula, much less the
common knowledge of the public in general. But the weather bureaus
of the airlines have worked by it for years, and pilots have to learn it.
It is indispensable both in commercial flying and in air war; we could fly
without gasoline, without aluminum, perhaps without radio, but we could
never do without Bjerknes's Air Mass Analysis.

You might inquire next whereThat morning's new air came from, and
just how it got to be cold, dry, and clear. And there you get close to the
heart of the new weather science, where meteorology turns into honest,
common-sense geography.

That air has come from Canada, where it has been quite literally air-
conditioned. Not all parts ~bf the world have the power to condition air,
but Canada has. Especially in the fall and winter and early spring, the
northern part of this continent becomes^ an almost perfectly designed
mechanical refrigeratoiTTrie "Rocky Mountains in the west keep currents
of new air from flowing intolBe" regBru And for weeks the air lies still.
The cool ground, much of it snow-covered; the ice of the frozen lakes;
plus the perennial stored-up coldness of Hudson's Bay — all cool the layer
of air immediately above them. This means a stabilizing and calming of
the whole atmosphere all the way up; for cool air is heavy^ and with a
heavy layer bottommost, there is none_of that upflowing of air, that up-
welling of moisture-laden heat into the cooler,Tiigh altitude which is the
mechanism that makes cloud siTHus there may be some low ground fogs
there, but above them the long nights of those northern latitudes are clear
and starry, wide open toward the black infinite spaces of the universe;
and into that black infinity the air gradually radiates whatever warmth it
may contain from its previous sojourns over other parts of the world*

134 THE EARTH

The result, after weeks of stagnation, is a huge mass of air that is uni-
formly ice-cold, dry, and clear. It stretches from the Rocky Mountains
in the west to Labrador in the east, from the ice wastes of the Arctic to the
prairies of Minnesota and North Dakota; and — the third dimension is the
most important — it is ice-cold from the ground all the way up to the
stratosphere. It is, in short, a veritable glacier of air.

That is an air mass. In the jargon of air-faring men, a mass of JPolar
Canadian' ain"

When a wave of good, fresh Polar Canadian air sweeps southward into
the United States — it happens almost rhythmically every few days — you
don't need a barometer to tell you so. There is nothing subtle, theoretical,
or scientific about it. You can see and feel the air itself and even hear it. It
comes surging out of a blue-green sky across the Dakptas, shaking the
hangar doors, whistling in the grassTputting those red-checkered thick
woolen jackets on the men, and lighting the stoves in the houses. It flows
southward down the Mississippi Valley as a cold wave in winter, or as
relief from a heat wave in summer, blowing as a northwest wind with
small white hurrying clouds in it. In winter it may sweep southward as
far as Tennessee and the Carolinas, bringing frosts with brilliantly^clear
skies, making the darkies shiver in their drafty cabins, and producing a
wave of deaths by pneumonia. Sometimes it even reaches the Texas Gulf
Coast; then it is locally called a norther, and the cows at night crowd for
warmth around the gas flares in the oil fields. A duck hunter dies of
exposure in the coastal swamps. A lively outbreak of Polar Canadian air
may reach down into Florida, damage the orange crops, and embarrass
local Chambers of Commerce. And deep outbreaks have been observed to
drive all the way down to Central America, where they are feared as a
fierce wind called the Tehuantepecer.

Polar Canadian is only one of many sorts of air. To put it in the
unprecise language of the layman, the great Norwegian discovery is that
air must always be of some distinct type: that it is never simply air but
always conditioned and flavored. What we call weather is caused by
gigantic waves in the air ocean which flood whole countries and conti-
nents for days at a stretch with one sort of air or another. And there is
nothing theoretical about any of these various sorts of air.

Each kind is easily seen and felt and sniffed, and is, in fact, fairly
familiar even to the city dweller, although he may not realize it. Each has
its own peculiar characteristics, its own warmth or coolness, dampness or
dryness, milkiness or clearness. Each has its own quality of light. In each,
smoke behaves differently as it pours from the chimneys: in some kinds
of air it creeps lazily, in some it bubbles away, in some it floats in layers-

WHAT MAKES THE WEATHER 135

That is largely why the connoisseur can distinguish different types of air
by smell.

Each type of air combines those qualities into an "atmosphere" of its
own. Each makes an entirely different sort of day. In fact, what sort of day
it is — raw, oppressive, balmy, dull, a "spring" day — depends almost entirely
upon the sort of air that lies over your particular section of the country at
that particular time.

And if you tried to describe the day in the old-fashioned terms — wind
direction and velocity, humidity, state of the sky — you could never quite
express its particular weather; but you can by naming the sort of air. An
airplane pilot, once he is trained in the new weather thinking, can get
quite impatient with the attempts of novelists, for instance, to describe
weather. "Why don't you say it was Polar Canadian air and get on with
your story?"

And if you are a connoisseur of airs just about the first thing you will
note every morning is something like, "Ah, Caribbean air to-day"; or if
you are really a judge you can make statements as detailed as, "Saskatch-
ewan air, slightly flavored by the Great Lakes."

For just as wines do, the airs take their names and their flavors from
the regions where they have matured. Of the seven airs that make up the
American weather, one is quite rare and somewhat mysterious. It is
known by the peculiarly wine-like name of Sec Superieur. It is believed
to be of tropical origin, but it comes to this continent after spending weeks
in the stratosphere somewhere above the Galapagos Islands. It is usually
found only high aloft, and interests pilots more than farmers. But once
in a while a tongue of it reaches the ground as hot, extremely dry, very
clear weather; and wherever it licks there is a drought.

The other six airs all come from perfectly earthly places, though far-
away ones. The easiest to recognize, the liveliest, is Polar Canadian. Its
opposite number in the American sky is Trnpicd JGlilf ^r Trnpirrrf
AtlagtJ£.(<Jaiirr-the steamy, warm air of the Eastern and MidvE&§j£rn
summer^ the kind Hiaf "comes alHTsotfftTfl^ starts people to

taflungabout heat and humidity, the kind that is sometimes so steamy that
it leaves you in doubt as to whether the sky means to be blue or overcast.
This air is brewed of hot sun and warm sea water in the Caribbean
region. The mechanism that does the air conditioning in this case is
mostly the daily afternoon thunderstorm which carries moisture and heat
high aloft in it.

Not quite SQ obvious is the origin of the moist, silvery, coolicbaununer^
cool-in-winter air that dominates the wcathciL^-Sga.tdf • It jscallej Polar
PaciBcpand it is a trick product. Its basic characteristics have been

136 THE EARTH

acquired over Siberia and it is cold and dry; but on its way across the
Pacific its lower five to ten thousand feet have been warmed up and
moistened. Sometimes such air comes straight across, reaching land in a
couple of days. Sometimes it hangs over the water for a week, and it
takes a good weatherman to predict just what sort of weather it will
produce.

Its counterpart is a flavor known as Tropical Pacific. That is the air they
sell to tourists in Southern California. It is really just plain South Seas
air, though the story here too is not as clear-cut as it might be.

A clear-cut type is Polar Atlaruic^ir. It sometimes blows down the New
England coast as a nor'easter, cold, rainy, with low clouds. It is simply
a chunk of the Grand Banks off Newfoundland gone traveling, and you
can almost smell the sea.

And one air that every tourist notices in the Southwest is Tropical Con-'
tinental. Its source region is the deserts of Arizona and Mexico. It is dry
and hot and licks up moisture so greedily that it makes water feel on youf
skin as chilly as if it were gasoline. It is not an important one for America,
though its European counterpart, Saharan air, is important for Europe.
Oklahoma, Colorado, and Kansas are as far as it ever gets; but even so,
a few extra outbreaks of it per year, and we have a dust bowl.

ii

The air mass idea is simple. As great ideas often do, the air mass idea
makes you feel that you have known it right along. And in a vague way,
you have. Take, for example, that half-brag, half-complaint of the Texans
that there is nothing between Texas and the North Pole to keep out those
northers but a barbed wire fence: it contains the kernel of the whole idea —
the invading air mass — but only in a fooling way. Or take the manner in
which the Mediterranean people have always given definite names to cer-
tain winds (boreas, sirocco, mistral) that blow hot or cold, dry or moist,
across their roofs. They are names, however, without the larger view. In
creative literature such things as a cold front passage — the sudden arrival
of a cold air mass — have been described several times quite accurately,
but always as a local spectacle, with the key thought missing.

Actually it took genius to see it. For air is a mercurial fluid, bubbly,
changeable; it is as full of hidden energies as dynamite; it can assume the
most unexpected appearances. There are days, to be sure, when the air
virtually advertises its origin. Offhand, you might say that on perhaps half
the days of the year it does. But there are also days when it$ appearance is
altogether misleading.

Take, for example, the amazing metamorphosis that happens to

WHAT MAKES THE WEATHER 137

Tropical Gulf air when it flows northward across the United States in
winter. It starts out from among the Islands looking blue and sunny and
like an everlasting summer afternoon. When it arrives over the northern
United States that same air appears as a dark-gray shapeless, drizzling over-
cast, and in the office buildings of New York and Chicago the electric
lights are on throughout what is considered a shivery winter day. It is
still the same air; if we could mix a pink dye into the air, as geographers
sometimes mix dyes into rivers to trace the flow of water, a cloud of pink
air would have traveled from Trinidad to New York. It has hardly
changed at all its actual contents of heat and water; but as far as its
appearance and its feel are concerned — its "weather" value — a few days
of northward traveling have reversed it almost into a photographic nega-
tive of itself.

What happens in this particular case — and it accounts for half our winter
days — is simply that the cool ground of the wintry continent chills this
moist, warm air mass — chills it just a little, not enough to change its
fundamental character, and not all the way up into its upper levels, but in
its bottommost Ir.yer and that only just enough to make it condense out
some of its abundant moisture in the form of visible clouds; it is quite
similar to the effect of a cold window pane on the air of a well-heated,
comfortable room — there is wetness and cooling right at the window, but
the bulk of the room's air is not affected.

Perhaps the oddest example of this is the trick by which Polar Pacific
air, striking the United States at Seattle, cool and moist, arrives in eastern
Montana and the Dakotas as a chinook, a hot, dry, snow-melting wind.

As Polar Pacific air flows up the slopes of the Sierras and the Cascades
it is lifted ten thousand feet into the thinner air of higher altitude. By one
law of physics the lifting should chill the air through release of pressure.
If you have ever bled excess pressure out of your tires you know this cool-
ing by release of pressure — you know how ice-cold the air comes hissing
out. But in this case, by a different law of physics, Polar Pacific reacts by
cooling only moderately; then it starts condensing out its moisture and
thereby protecting its warmth; hence the tremendous snowfalls of the
sierras, the giant redwoods, the streams that irrigate California ranches.

Once across the Cascades and the Sierras, the air flows down the eastern
slopes. In descending it comes under pressure and therefore heats up, just
as air heats up in a tire pump. Warmed, the air increases its capacity to
hold moisture; it becomes relatively drier — thus this air sucks back its
own clouds into invisible form. When it arrives over the Columbia Basin,
or the country round Reno, or Owens Valley, it is regular desert air —
warm, very clear, and very dry. That is why the western deserts are

138 THE EARTH

where they are. Flowing on eastward, it comes against another hump,
the Continental Divide and the Rockies. Here the whole process repeats
itself. Again the air is lifted and should become ice-cold; again it merely
cools moderately, clouds up, and drops its remaining moisture to protect
its warmth; hence the lush greenery of Coeur d'Alene, the pine forests
of New Mexico. Finally, as the air flows down the eastern slope of the
Rockies, compression heats it once more, as in the bicycle pump. Twice
on the way up it has dropped moisture and thus failed to cool; twice
on the way down it has been heated : it is now extremely dry, and twenty
degrees warmer than it was at Seattle. That is the chinook, a wind
manufactured of exactly the sort of principles that work in air-condition-
ing machinery, and a good example of the trickery of air masses. But it
is still a simple thing; it is still one actual physically identical mass of air
that you are following. It you had put pink smoke into it at Seattle, pink
smoke would have arrived in South Dakota.

That is how the air mass concept explains all sorts of weather detail:
the various kinds of rain — showery or steady; the many types of cloud —
low or high, solid or broken, layered or towering; thunderstorms; fog.
An air mass, thus-and-thus conditioned, will react differently as it flows
over the dry plains, the freshly plowed cotton fields, the cool lakes, the
hot pavements, the Rocky Mountains of the United States.

An airplane pilot's weather sense consists largely of guessing the exact
manner in which a given sort of air will behave along his route. Tropical
Gulf in summer over Alabama? Better not get caught in the middle after-
noon with a low fuel reserve. We shall have to detour around many
thunderstorms. The details are as multifarious as geography itself, but
much of it has by now been put into the manuals, and the pilot memorizes
such items as these:

Canadian air that passes over the Great Lakes in winter is moistened
and warmed in its lower layers and becomes highly unstable. When such
air hits the rolling country of western Pennsylvania and New York and
the ridges of the Appalachians the hills have a sort of "trigger action"
and cause snow flurries or rain squalls with very low ceilings and visibility.

In summer, Canadian air that flows into New England, dried, without
passing over the Great Lakes, will be extremely clear and extremely
bumpy.

Tropical Gulf over the South forms patchy ground fog just before
sunrise that will persist for two or three hours.

As Polar Pacific air moves southward along the Pacific Coast it forms
a layer of "high fog."

WHAT MAKES THE WEATHER 139

In Colorado and Nebraska fresh arriving Canadian air frequently shows
as a dust storm.

Given two types of country underneath, one kind of air can produce
two sorts oi weather only a few miles apart. Tropical Atlantic air, for
instance, appears over the hills of New England as hot and summery
weather, slightly hazy, inclined toward afternoon thunderstorms. A few
miles of? the coast the same air appears as low banks of fog. That is
because the granite and the woods are warmed all through, and actually
a little warmer than Tropical Gulf air itself, at least during the day;
while the ocean is much colder than the air, and cools it.

Again, one kind of country can have opposite effects on two different
types of air. For example, the farms of the Middle West in the spring
when the frost is just out of the ground: that sort of country feels cool
to Tropical Gulf air that has flowed up the Mississippi Valley. The bottom
layers of that warm moist air are chilled and thus the whole air mass is
stabilized. It will stay nicely in layers; the clouds will form a flat, level
overcast; smoke will spread and hover as a pall. But to a mass of freshly
broken-out Canadian air that sort of country feels warm. The air in
immediate contact with the ground is warmed, and the whole mass
becomes bottom-light and unstable.

And that means action: a commotion much like the boiling of water
on a huge scale and in slow motion. The warmed air floats away upward
to the colder air aloft, forming bubbles of rising air, hundreds of feet
in diameter, that are really hot-air balloons without a skin.

Those rising chunks of air are felt by fliers as bumps. When the ship
flies into one it gets an upward jolt; when it flies out again it gets a down-
ward jolt. They are what makes it possible to fly a glider, even over flat
country; all you have to do is to find one of those bubbles, stay in it by
circling in a tight turn, and let it carry you aloft.

The clear air, the tremendous visibility of such a day is itself the result
of instability: the rising bubbles carry away the dust, the haze, the indus-
trial smoke. The air is always roughest on one of those crisp, clear, newly
washed days. If the rising air gets high enough it makes cumulus clouds,
those characteristic, towering, puffy good-weather clouds. That sort of
cloud is nothing but a puff of upward wind become visible. The rise
has cooled the air and made its water vapor visible. Soaring pilots seek
to get underneath a cumulus cloud — there is sure to be a lively upflow
there. Sometimes, in really unstable air, the rising of the air reaches
hurricane velocities. We call that a thunderstorm, but the lightning and
thunder are only by-products of the thing. The thing itself is simply a
vicious, explosive upsurging of air: the wind in thunderstorms blows

140 THE EARTH

sixty to one hundred miles per hour — straight up! The most daring of
soaring pilots have flown into thunderstorms and have been sucked up
almost to the stratosphere.

The weatherman, unlike the pilot, need not guess. He has got a slide
rule; he has got the laws of gases, Charles's Law, Boyle's Law, Buys
Ballot's Law at his fingertips. He has studied thermodynamics, and he
has got a new device that is the biggest thing in weather science since
Torricelli invented the barometer — the radio sonde with which he can
take soundings of the upper air, find out just how moisture and tempera-
ture conditions are aloft, just how stable or unstable the air will be, at
what level the clouds will form, and of what type they will be.

Radio sondes go up in the dead of night from a dozen airports all over
the continent. The radio sonde looks like a box of candy, being a small
carton wrapped in tinfoil; but it is actually a radio transmitter coupled
to a thermometer and a moisture-meter. It is hung on a small parachute
which is hitched to a balloon. It takes perhaps an hour for the balloon
to reach the stratosphere, and all the time it signals its own readings in
a strange, quacky voice, half Donald Duck, half voice from the beyond.
Then it stops. You know that the balloon has burst, the parachute is
letting the instrument down gently.

The next morning some farm boy finds the shiny thing in a field, with
a notice attached offering a reward for mailing it back to the weather
bureau.

Also the next morning a man in Los Angeles paces up and down his
office, scanning the wall where last night's upper-air soundings are tacked
up. Emitting heavy cigar smoke and not even looking out of the window,
he dictates a weather forecast for the transcontinental airway as far east
as Salt Lake City, a forecast that goes into such detail that you sometimes
think he is trying to show off.

in

With the air mass idea as a key, you can make more sense out of the
weather than the professional weatherman could before Bjerknes; and
even if you don't understand Boyle's Law and all the intricate physics
of the atmosphere, you can do a quite respectable job of forecasting.

It goes like this : suppose you are deep in Caribbean air. You will have
"air mass weather": a whole series of days of the typical sort that goes
with that particular type of air when it overlies your particular section of
the country in that particular season. There will be all sorts of minor
changes; there will be a daily cycle of weather, clouds, perhaps thunder-
storms, or showers; but essentially the weather will be the same day aftet

WHAT MAKES THE WEATHER 141

day. Any real change in weather can come only as an incursion of a new
air mass — probably Polar Canadian.

And when that air mass comes you will know it. New air rarely comes
gently, gradually, by imperceptible degrees; almost always the new air
mass advances into the old one with a clear-cut, sharply defined forward
front. Where two air masses adjoin each other you may in half an hour's
driving — in five minutes' flying — change your entire weather, travel
from moist, muggy, cloudy weather into clear, cool, sunny weather.
That clear-cut boundary is exactly what makes an air mass a distinct
entity which you can plot on a map and say, "Here it begins; here it
ends"; these sharp boundaries of the air masses are called "fronts" and
are a discovery as important as the air mass itself.

You are watching, then, for a "cold front," the forward edge of an
advancing mass of cold air. You will get almost no advance warning.
You will see the cold air mass only when it is practically upon you. But
you know that sooner or later it must come, and that it will come from
the northwest. Thus, an occasional long-distance call will be enough-
Suppose you are in Pittsburgh, with a moist, warm southwest wind: the
bare news that Chicago has a northerly wind might be enough of a clue..
If you knew also that Chicago was twenty degrees cooler you would be
certain that a cold air mass had swamped Chicago and was now presum-
ably on its way to Pittsburgh, traveling presumably at something like
30 m.p.h. You could guess the time of arrival of its forward front within
a few hours. That is why the most innocent weather reports are now
so secret; why the British censor suppresses snow flurries in Scotland;,
why a submarine in the Atlantic would love to know merely the wind
direction and temperature at, say, Columbus, Ohio; why the Gestapo*
had that weather station in Greenland.

Knowing that a cold front is coming, you know what kind of weather
to expect; though some cold fronts are extremely fierce, and others quite
gentle (noticeable only if you watch for them), the type is always the
same. It is all in the book — Bjerknes described it and even drew pictures
of it. It was the advance of such a cold front which occurred while you
slept that night before you awoke to find the world fresh and newly
painted.

Cold air is heavy; as polar air plows into a region occupied by tropical
air it underruns; it gets underneath the warm air and lifts it up even
as it pushes it back. A cold front acts physically like a cowcatcher.

Seen from the ground, the sequence of events is this: an hour or two-
before the cold front arrives the clouds in the sky become confused,,
somewhat like a herd of cattle that smells the coyotes; but you observe-

142 THE EARTH

that by intuition rather than by measurable signs. Apart from that, there
are no advance signs. The wind will be southerly to the last, and the air
warm and moist.

Big cumulus clouds build up all around, some of them with dark
bases, showers, and in summer thunder and lightning — that is the warm
moist air going aloft. A dark bank of solid cloud appears in the north-
west, and though the wind is still southerly, this bank keeps building up
and coming nearer: it is the actual forward edge of the advancing cold
air. When it arrives there is a cloudburst. Then the cold air comes sweep-
ing in from the northwest with vicious gusts. This is the squall that cap-
sizes sailboats and uproots trees, flattens forests and unroofs houses.

The whole commotion probably is over in half an hour. The wind eases
up, though it is still cool and northwesterly, the rain ceases, the clouds
break and new sky shows: the front has passed, the cold air mass has
arrived.

The weatherman can calculate these things too. He has watched and
sounded out each of the two air masses for days or even weeks, ever
since it moved into his ken somewhere on the outskirts of the American
world. Thus an airline weatherman may look at a temperature-moisture
graph and say, "This is dynamite. This air will be stable enough as long
as it isn't disturbed. But wait till some cold air gets underneath this and
starts lifting it. This stuff is going to go crazy."

In making your own guess you would take the same chance that the
weatherman takes every morning — that you might be right and yet get
an error chalked up against you. Suppose the Chicago weatherman,
seeing a cold front approach, forecasts thunderstorms. One thunderstorm
passes north of the city, disturbing the 30,000 inhabitants of Waukegan.
Another big one passes south of Chicago, across farms just south of Ham-
mond, Ind., affecting another 30,000 people. None happens to hit Chicago
itself, with its 3 million people. On a per capita basis, the weatherman was
98 per cent wrong! Actually he was right.

Now you are in the cold air mass, and you can reasonably expect "air
mass weather" for a while rather than "frontal" weather; />., a whole
series of whatever sort of day goes with Canadian air in your particular
section of the country at that particular season.

Any real change in the weather nous can again come only with an
incursion of a new and different air mass— and now that will probably
mean tropical maritime air of the Gulf kind. To forecast that invasion
is no trick at all: you can see the forward front of the warm air mass
in the sky several days before it sweeps in on the ground. Warm air is
light. As Caribbean air advances into a region occupied by Canadian air

WHAT MAKES THE WEATHER 143

it produces a pattern that is the exact opposite of the cold front. The
warm front overhangs forward, overruns the cold air; the warm air mass
may appear high above Boston when at ground level it is just invading
Richmond, Va.

Again the sequence of events is predictable — Bjerknes drew the picture.
It is the approaching warm front that makes for "bad" weather, for rain
of the steady, rather than the showery kind, for low ceilings.

Consider a warm front on the morning when its foot is near Rich-
mond and its top over Boston. Boston that morning sees streaks of cirrus
in its sky — "mares' tails," the white, feathery, diaphanous cloud arranged
in filaments and bands, that is so unsubstantial that the sun shines clear
through it and you are hardly conscious of it as a cloud — and actually it
doesn't consist of water droplets, as do most clouds, but of ice crystals.
New Haven the same morning has the same kind of cloud, but slightly
thicker, more nearly as a solid, milky layer. New York that same morning
sees the warm air as a gray solid overcast at 8,000 feet. Philadelphia has
the same sort of cloud at 5,000, with steady rain. Washington has 1,500
feet, rain. Quantico and Richmond report fog, and all airplanes are
grounded. Raleigh, N.C., has clearing weather, the wind has shifted that
morning to the southwest, and it is getting hot and humid there. Raleigh
would be definitely behind the front, well in the warm air mass itself.

By nightfall Boston has the weather that was New Haven's in the
morning. The moon, seen through a milky sheet of cirrus clouds, has a
halo: "There is going to be rain." New Haven that night has New York's
weather of that morning; New York has Philadelphia's; and so on down
the line — the whole front has advanced one hundred miles. In fore-
casting the weather for Boston it is safe to guess that Boston will get in
succession New Haven weather, New York weather, Philadelphia,
Washington, Richmond weather — and finally Raleigh weather — in a
sequence that should take two or three days: steady lowering clouds,
rainy periods, some fog — followed finally by a wind shift to the southwest,
and rapid breaking of clouds, and much warmer, very humid weather.

And then the cycle begins all over. You are then deep in Caribbean
air again. You will have Caribbean air mass weather, and your weather eye
had better be cocked northwest to watch for the first signs of polar air.

IV

There is a rhythm, then, in the weather, or at least a sort of rhyme,
a repetitive sequence. All those folk rules that attribute weather changes
to the phases of the moon, or to some other simple periodicity ("If the
weather is O.K. on Friday, it is sure to rain over the week-end") are

144 THE EARTH

not so far from the mark after all. The rhythm does not work in terms
of rain or shine; but it does work in terms of air masses; and thus,
indirectly and loosely, through the tricky physics of the air, it governs
also the actual weather.

What makes the air masses move, and what makes them move
rhythmically — that is the crowning one of the great Norwegian discov-
eries. Some of it had long been known. It was understood that the motive
power is the sun. By heating the tropics and leaving the polar region
cold, it sets up a worldwide circulation of air, poleward at high altitude,
equatorward at lower levels. It was understood that this simple circulation
is complicated by many other factors such as the monsoon effect: conti-
nents heat up in summer and draw air in from over the ocean, in winter
they cool and air flows out over the ocean; there was the baffling Coriolis
Force that makes all moving things (on the Northern Hemisphere)
curve to the right. In everyday life we don't notice it, but some geogra-
phers hold that it affects the flow of rivers, and artillerymen make allow-
ance for it: a long-range gun is always aimed at a spot hundreds of yards
to the left of the target. The monsoons and the Coriolis Force between
them break up the simple pole-to-equator-to-pole flow of the air into a
worldwide complicated system of interlocking "wheels" — huge eddies
that show variously as tradewinds, calm belts, prevailing westerlies.
Charts have been drawn of the air ocean's currents showing how air is
piled up over some parts of the world, rushed away from others.

But it remained for the Norwegians to discover the polar front —
perhaps the last-discovered geographical thing on this earth. Bjerknes
himself first saw it — that the worldwide air circulation keeps piling up
new masses of polar air in the north and pressing them southward; it
keeps piling up new masses of tropical air in the south, pressing them
northward; and thus forever keeps forcing tropical and polar air masses
against each other along a front; that the demarcation line between
tropical air masses, pressing northward, and polar air masses, pressing
southward, runs clear around the world: through North America and
across the Atlantic, through Europe and across Siberia, through Japan
and across the Pacific. The polar front is clear-cut in some places, tends
to wash out in others; but it always reestablishes itself.

In summer, the polar front runs across North America north of the
Great Lakes; in winter, it takes up a position across the United States.
Wherever it is, it keeps advancing southward, retreating northward,
much like a battlefront. And all the cold fronts and warm fronts are
but sections of this greater front.

The rhythmical flowing of the air masses, the Norwegians discovered,

WHAT MAKES THE WEATHER 145

is simply this wave action along the polar front. Like all the rest of the
modern weather concepts, this one becomes common sense, almost self-
evident — the moment you realize that air is stuff, a real fluid that has
density and weight. Except that it occurs on a scale of unhuman mag-
nitude, wave action along the polar front is almost exactly the same thing
as waves on a lake.

In a lake, a dense, heavy fluid — the water — lies underneath a thin, light
fluid — the air — and the result is that rhythmical welling up and down
of the lake-surface that we call waves. Along the polar front, a dense,
heavy fluid, the polar air, lies to the north of a thin, lighter fluid, the
tropical air; the result is a rhythmical welling southward and northward
of the two kinds of air. When a water wave rolls across a lake its first
manifestation is a downward bulging of the water, then an upward
surging. When a wave occurs in the polar front it appears first as a
northward surging of warm air, and that means all the phenomena of a
warm front. Then, in the rhythmical backswing, comes the southward
surging of cold air, and that means all the phenomena of a cold front.

These waves are bigger than the imagination can easily encompass.
They measure 500 to 1,000 miles from crest to crest. When tropical air
surges northward it will wash to the edge of the Arctic; when Polar air
surges southward it reaches down into the tropics. Such a wave will
travel along the polar front all the way from somewhere out in the
Pacific, across the United States and out to the Atlantic; that is the
meteorological action which underlies the recent novel Storm by George
Stewart: the progress of a wave along the polar front.

So similar are these air waves to the air-water waves of a lake that there
are even whitecaps and breakers. What we call a whitecap or a breaker
is a whirling together of air and water into a white foam. In the great
waves along the polar front the same toppling-over can occur: warm and
cold air sometimes wheel around each other, underrun and overrun each
other, in a complicated, spiral pattern.

And that is where the old papery weather science of the schoolbooks
merges with the realistic observations of the Norwegians. You remember
about those Lows that were traveling across the weather map and brought
with them bad weather. You know how a dropping barometer has always
indicated the coming of bad weather — though we have never quite
known why.

Now it turns out that the barometric low is nothing but one of those
toppling-over waves in the polar front — or rather, it is the way in which
the spiral surging of the air masses affects the barometers. Look at the
Middle West when it is being swept by one of those waves, take a reading

146 THE EARTH

of everybody's barometer, and you get the typical low. Look at it when
a low is centered, watch the kinds of air that are flowing there, the wind
directions, the temperatures and humidities and you find that a low has
a definite internal structure: the typical wave pattern, with a warm air
mass going north and a cold air mass going south, both phases of the same
wave.

Barometric pressures turn out to be not the cause of the weather, but
simply a result, a rather unimportant secondary symptom of it. What
weather actually is the Norwegians have made clear. It is the wave
action of the air ocean.

7942

C. MATTER, ENERGY, PHYSICAL LAW

Newtoniana

"I do not know what 1 may appear to the world, but to myself I seem
to have been only like a boy playing on the sea-shore, and diverting myself
in now and then finding a smoother pebble and a prettier shell than or-
dinary, whilst the great ocean of truth lay all undiscovered before me." —
Sir Isaac Newton

"If I have seen farther than Descartes, it is by standing on the shoul-
ders of giants." — Sir Isaac Newton

"Newton was the greatest genius that ever existed and the most for-
tunate, for we cannot find more than once a system of the world to estab-
lish."— Lagrange

"There may have been minds as happily constituted as his for the
cultivation of pure mathematical science; there may have been minds
as happily constituted for the cultivation of science purely experimental;
but in no other mind have the demonstrative faculty and the inductive
faculty co-existed in such supreme excellence and perfect harmony." —
Lord Macaulay

"Taking mathematics from the beginning of the world to the time
when Newton lived, what he had done was much the better half." —
Leibnitz

"Let Men Rejoice that so great a glory of the human race has ap-
peared."— Inscription on Westminster Tablet

"The law of gravitation is indisputably and incomparably the greatest
scientific discovery ever made, whether we look at the advance which it
involved, the extent of truth disclosed, or the fundamental and satisfac-
tory nature of this truth." — William Whewell

"Newton's greatest direct contribution to optics, appears to be the
discovery and explanation of the nature of color. He certainly laid the

147

148 MATTER, ENERGY, PHYSICAL LAW

broad foundation upon which spectrum analysis rests, and out of this has
come the new science of spectroscopy which is the most delicate and
powerful method for the investigation of the structure of matter. — Dayton
C. Miller

"On the day of Cromwell's death, when Newton was sixteen, a great
storm raged all over England. He used to say, in his old age, that on that
day he made his first purely scientific experiment. To ascertain the force
of the wind, he first jumped with the wind and then against it, and by
comparing these distances with the extent of his own jump on a calm
day, he was enabled to compute the force of the storm. When the wind
blew thereafter, he used to say it was so many feet strong. — fames Parton

"His carriage was very meek, sedate and humble, never seemingly
angry, of profound thought, his countenance mild, pleasant and comely.
I cannot say I ever saw him laugh but once, which put me in mind of
the Ephesian philosopher, who laughed only once in his lifetime, to see
an ass eating thistles when plenty of grass was by. He always kept close
to his studies, very rarely went visiting anrJ had few visitors. I never
knew him to take any recreation or pastime either in riding out to take
the air, walking, bowling, or any other exercise whatever, thinking all
hours lost that were not spent in his studies, to which he kept so close
that he seldom left his chamber except at term time, when he read in
the schools as Lucasianus Professor, where so few went to hear him, and
fewer that understood him, that ofttimes he did in a manner, for want
of hearers read to the walls. Foreigners he received with a great deal of
freedom, candour, and respect. When invited to a treat, which was very
seldom, he used to return it very handsomely, and with much satisfac-
tion to himself. So intent, so serious upon his studies, that he ate very
sparingly, nay, ofttimes he has forgot to eat at all, so that, going into his
chamber, I have found his mess untouched, of which, when I have re-
minded him, he would reply — 'Have I?' and then making to the table
would eat a bite or two standing, for I cannot say I ever saw him sit at
table by himself. He very rarely went to bed till two or three of the
clock, sometimes not until five or six, lying about four or five hours,
especially at spring and fall of the leaf, at which times he used to em-
ploy about six weeks in his elaboratory, the fires scarcely going out
either night or day; he sitting up one night and I another till he had fin-
ished his chemical experiments, in the performance of which he was the
most accurate, strict, exact. What his aim might be I was not able to
penetrate into, but his pains, his diligence at these set times made me think
he aimed at something beyond the reach of human art and industry. I

NEWTONIANA 149

cannot say I ever saw him drink either wine, ale or beer, excepting at
meals and then but very sparingly. He very rarely went to dine in the
hall, except on some public days, and then if he has not been minded,
would go very carelessly, with shoes down at heels, stockings untied, sur-
plice on, and his head scarcely combed.

His elaboratory was well furnished with chemical materials, as bodies,
receivers, heads, crucibles, etc. which was made very litle use of, the
crucibles excepted, in which he fused his metals; he would sometimes, tho'
very seldom, look into an old mouldy book which lay in his elaboratory,
I think it was titled Agricola de Metallis, the transmuting of metals being
his chief design, for which purpose antimony was a great ingredient. He
has sometimes taken a turn or two, has made a sudden stand, turn'd
himself about, run up the stairs like another Archimedes, with an Eureka
fall to write on his desk standing without giving himself the leisure to
draw a chair to sit down on. He would with great acuteness answer a
question, but would very seldom start one. Dr. Boerhave, in some of his
writings, speaking of Sir Isaac: 'That man/ says he, "comprehends as
much as all mankind besides.' — Humphrey Newton

"When we review his life, his idiosyncrasies, his periods of contrast,
and his doubts and ambitions and desire for place, may we not take some
pleasure in thinking of him as a man — a man like most other men save
in one particular — he had genius — a greater touch of divinity than comes
to the rest of us? "—David Eugene Smith

Discoveries

SIR ISAAC NEWTON

CONCERNING THE LAW OF GRAVITATION

1THERTO WE HAVE EXPLAINED THE PHAENOMENA

of the heavens and of our sea by the power of gravity, but have
not yet assigned the cause of this power. This is certain, that it must
proceed from a cause that penetrates to the very centres of the sun and
planets, without suffering the least diminution of its force; that operates
not according to the quantity of the surfaces of the particles upon which
it acts (as mechanical causes used to do), but according to the quantity
of the solid matter which they contain, and propagates its virtue on all
sides to immense distances, decreasing always in the duplicate propor-
tions of the distances. Gravitation towards the sun is made up out of the
gravitations towards the several particles of which the body of the sun
is composed; and in receding from the sun decreases accurately in the
duplicate proportion of the distances as far as the orb of Saturn, as evi-
dently appears from the quiescence of the aphelions of the planets; nay,
and even to the remotest aphelions of the comets, if these aphelions are
also quiescent. But hitherto I have not been able to discover the cause
of those properties of gravity from phaenomena, and I frame no hypoth-
eses; for whatever is not deduced from the phaenomena is to be called
an hypothesis; and hypotheses, whether metaphysical or physical, whether
of occult qualities or mechanical, have no place in experimental phi-
losophy. In this philosophy particular propositions are inferred from the
phaenomena, and afterwards rendered general by induction. Thus it was
that the impenetrability, the mobility, and the impulsive force of bodies,
and the laws of motion and gravitation were discovered. And to us it is
enough that gravity does really exist, and act according to the laws which
we have explained, and abundantly serves to account for all the motions
of the celestial bodies, and of our sea.

From Newton's "Principia" edition of 1726
150

DISCOVERIES 151

LAWS OF MOTION

Law I. Every body perseveres in its state of rest, or of uniform motion
in a right line, unless it is compelled to change that state by force im-
pressed thereon.

Projectiles persevere in their motions, so far as they are not retarded
by the resistance of the air, or impelled downwards by the force of gravity.
A top, whose parts by their cohesion are perpetually drawn aside from
rectilinear motions, does not cease its rotation, otherwise than as it is
retarded by the air. The greater bodies of the planets and comets, meet-
ing with less resistance in more free spaces, preserve their motions both
progressive and circular for a much longer time.

Law II. The alteration of motion is ever proportional to the motive
force impressed '; and is made in the direction of the right line in which
that force is impressed.

If any force generates a motion, a double force will generate double
the motion, a triple force triple the motion, whether that force be im-
pressed altogether and at once, or gradually and successively. And this
motion (being always directed the same way with the generating force),
if the body moved before, is added to or subducted from the former
motion, according as they directly conspire with or are directly contrary
to each other; or obliquely joined, when they are oblique, so as to pro-
duce a new motion compounded from the determination of both.

Law III. To every action there is always opposed an equal reaction; or
the mutual actions of two bodies upon each other are always equal, and
directed to contrary parts.

Whatever draws or presses another is as much drawn or pressed by
that other. If you press a stone with your finger, the finger is also pressed
by the stone. If a horse draws a stone tied to a rope, the horse (if I may so
say) will be equally drawn back towards the stone; for the distended rope,
by the same endeavor to relax or unbend itself, will draw the horse
as much towards the stone, as it does the stone towards the horse, and
will obstruct the progress of the one as much as it advances that of the
other. If a body impinge upon another, and by its force change the mo-
tion of the other, that body also (because of the equality of the mutual
pressure) will undergo an equal change, in its own motion, towards the
contrary part. The changes made by these actions are equal, not in the
velocities but in the motions of bodies; that is to say, if the bodies are
not hindered by any other impediments. For, because the motions are
equally changed, the changes of the velocities made towards contrary
parts are reciprocally proportional to the bodies.

From Newton's "Principia" edition of 7726

152 MATTER, ENERGY, PHYSICAL LAW

THE DISPERSION OF LIGHT

In the year 1666 (at which time I applied myself to the grinding of
optick glasses of other figures than spherical) I procured me a trian-
gular glass prism, to try therewith the celebrated phaenomena of colours.
And in order thereto, having darkened my chamber, and made a small
hole in my window-shuts, to let in a convenient quantity of the sun's
light, I placed my prism at its entrance, that it might be thereby re-
fracted to the opposite wall. It was at first a very pleasing divertissement,
to view the vivid and intense colours produced thereby; but after a while
applying myself to consider them more circumspectly, I became surprised,
to see them in an oblong form; which, according to the received laws
of refraction, I expected should have been circular. They were terminated
at the sides with straight lines, but at the ends, the decay of light was so
gradual that it was difficult to determine justly, what was their figure;
yet they seemed semicircular.

Comparing the length of this coloured Spectrum with its breadth, I
found it about five times greater, a disproportion so extravagant, that it
excited me to a more than ordinary curiosity to examining from whence
it might proceed. I could scarce think, that the various thicknesses of
the glass, or the termination with shadow or darkness, could have any
influence on light to produce such an effect; yet I thought it not amiss,
first to examine those circumstances, and so try'd what would happen
by transmitting light through parts of the glass of divers thicknesses, or
through holes in the window of divers bignesses, or by setting the prism
without, so that the light might pass through it, and be refracted, before
it was terminated by the hole: But I found none of these circumstances
material. The fashion of the colours was in all these cases the same. . . .
The gradual removal of these suspicions led me to the Experimentum
Crucis, which was this: I took two boards, and placed one of them close
behind the prism at the window, so that the light might pass through a
small hole, made in it for the purpose, and fall on the other board, which
I placed at about 12 feet distance, having first made a small hole in it
also, for some of the incident light to pass through. Then I placed an-
other prism behind this second board, so that the light trajected through
both the boards might pass through that also, and be again refracted be-
fore it arrived at the wall. This done, I took the first prism in my hand,
and turned it to and fro slowly about its axis, so much as to make the
several parts of the image cast, on the second board, successively pass
through the hole in it, that I might observe to what places on the wall
the second prism would refract them. And I saw by the variation of those

DISCOVERIES 153

places, that the light, tending to that end of the image, towards which
the refraction of the first prism was made, did in the second prism suffer a
refraction considerably greater than the light tending to the other end.
And so the true cause of the length of that image was detected to be no
other, than that light is not similar or homogenial, but consists of
Difform Rays, some of which are more Refrangible than others; so that
without any difference in their incidence on the same medium, some shall
be more Refracted than others; and therefore that, according to their
particular Degrees of Refrangibility, they were transmitted through the
prism to divers parts of the opposite wall. . . .

On the Origin of Colours

The colours of all natural bodies have no other origin than this, that
they are variously qualified, to reflect one sort of light in greater plenty
than another. And this I have experimented in a dark room, by illumi-
nating those bodies with uncompounded light of divers colours. For by
that means any body may be made to appear of any colour. They have
there no appropriate colour, but ever appear of the colour of the light
cast upon them, but yet with this difference, that they are most brisk
and vivid in the light of their own daylight colour. Minium appeareth
there of any colour indifferently, with which it is illustrated, but yet most
luminous in red, and so bise appeareth indifferently of any colour, but
yet most luminous in blue. And therefore minium reflecteth rays of any
colour, but most copiously those endowed with red, that is, with all
sorts of rays promiscuously blended, those qualified with red shall abound
most in that reflected light, and by their prevalence cause it to appear
of that colour. And for the same reason bise, reflecting blue most copiously,
shall appear blue by the excess of those rays in its reflected light; and
the like of other bodies. And that this is the entire and adequate cause
of their colours, is manifest, because they have no power to change or
alter the colours of any sort of rays incident apart, but put on all colours
indifferently, with which they are enlightened.

These things being so, it can be no longer disputed, whether there be
colours in the dark, or whether they be the qualities of the objects we
see, no nor perhaps, whether light be a body. For, since colours are the
quality of light, having its rays for their entire and immediate subject,
how can we think those rays qualities also, unless one quality may be the
subject of, and sustain another; which in effect is to call it substance.
We should not know bodies for substances; were it not for their sensible
qualities, and the principle of those being now found due to something
else, we have as good reason to believe that to be a substance also.

154 MATTER, ENERGY, PHYSICAL LAW

Besides, who ever thought any quality to be a heterogeneous aggregate,
such as light is discovered to be? But to determine more absolutely what
light is, after what manner refracted, and by what modes or actions it
produceth in our minds the phantasms of colours, is not so easie; and
I shall not mingle conjectures with certainties.

From Newton's "A New Theory about Light and Colours," 1672

Mathematics, the Mirror of Civilization

LANCELOT HOGBEN

From Mathematics for the Million

npHERE IS A STORY ABOUT DIDEROT, THE

A Encyclopaedist and materialist, a foremost figure in the intellectual
awakening which immediately preceded the French Revolution. Diderot
was staying at the Russian court, where his elegant flippancy was enter-
taining the nobility. Fearing that the faith of her retainers was at stake,
the Tsaritsa commissioned Euler, the most distinguished mathematician
of the time, to debate with Diderot in public. Diderot was informed that a
mathematician had established a proof of the existence of God. He was
summoned to court without being told the name of his opponent. Before
the assembled court, Euler accosted him with the following pronounce-

a + bn

ment, which was uttered with due gravity: " = x, done Dieu

n

existe repondez!" Algebra was Arabic to Diderot. Unfortunately he did
not realize that was the trouble. Had he realized that algebra is just a
language in which we describe the sizes of things in contrast to the
ordinary languages which we use to describe the sorts of things in the
world, he would have asked Euler to translate the first half of the sentence
into French. Translated freely into English, it may be rendered: "A
number x can be got by first adding a number a to a number b multiplied
bv itself a certain number of timesa and then dividing the whole by the

MATHEMATICS, THE MIRROR OF CIVILIZATION 155

number of £'s multiplied together. So God exists after all. What have
you got to say now?" If Diderot had asked Euler to illustrate the first
part of his remark for the clearer understanding of the Russian court,
Euler might have replied that x is 3 when a is i and b is 2 and n is 3, or
that x is 21 when a is 3 and b is 3 and n is 4, and so forth. Euler's troubles
would have begun when the court wanted to know how the second part
of the sentence follows from the first part. Like many of us, Diderot had
stagefright when confronted with a sentence in size language. He left
the court abruptly amid the titters of the assembly, confined himself to
his chambers, demanded a safe conduct, and promptly returned to France.

Though he could not know it, Diderot had the last laugh before the
court of history. The clericalism which Diderot fought was overthrown,
and though it has never lacked the services of an eminent mathematician,
the supernaturalism which Euler defended has been in retreat ever since.
One eminent contemporary astronomer in his Gifford lectures tells us that
Dirac has discovered p and q numbers. Done Dieu existe. Another distin-
guished astronomer pauses, while he entertains us with astonishing calcu-
lations about the distance of the stars, to award M. le grand Architects
an honorary degree in mathematics. There were excellent precedents long
before the times of Euler and Diderot. For the first mathematicians were
the priestly calendar makers who calculated the onset of the seasons. The
Egyptian temples were equipped with nilometers with which the priests
made painstaking records of the rising and falling of the sacred river.
With these they could predict the flooding of the Nile with great accuracy.
Their papyri show that they possessed a language of measurement very
different from the pretentious phraseology with which they fobbed off
their prophecies on the laity. The masses could not see the connection
between prophecy and reality, because the nilometers communicated with
the river by underground channels, skilfully concealed from the eye of
the people. The priests of Egypt used one language when they wrote in
the proceedings of a learned society and another language when they gave
an interview to the "sob sisters" of the Sunday press.

In the ancient world writing and reading were still a mystery and
a craft. The plain man could not decipher the Rhind papyrus in which
the scribe Ahmes wrote down the laws of measuring things. Civilized
societies in the twentieth century have democratized the reading and
writing of sort language. Consequently the plain man can understand
scientific discoveries if they do not involve complicated measurements.
He knows something about evolution. The priestly accounts of the crea-
tion have fallen into discredit. So mysticism has to take refuge in the
atom. The atom is a safe place not because it is small, but because you

156 MATTER, ENERGY, PHYSICAL LAW

have to do complicated measurements and use underground channels to
find your way there. These underground channels are concealed from
the eye of the people because the plain man has not been taught to read
and write size language. Three centuries ago, when priests conducted
their services in Latin, Protestant reformers founded grammar schools
so that people could read the open bible. The time has now come for
another Reformation. People must learn to read and write the language
of measurement so that they can understand the open bible of modern
science.

In the time of Diderot the lives and happiness of individuals might still
depend on holding the correct beliefs about religion. Today the lives and
happiness of people depend more than most of us realize upon the correct
interpretation of public statistics which are kept by Government offices.
When a committee of experts announce that the average man can live
on his unemployment allowance, or the average child is getting sufficient
milk, the mere mention of an average or the citation of a list of figures
is enough to paralyse intelligent criticism. In reality half or more than
half the population may not be getting enough to live on when the
average man or child has enough. The majority of people living today in
civilized countries cannot read and write freely in size language, just as
the majority of people living in the times of Wycliff and Luther were
ignorant of Latin in which religious controversy was carried on. The
modern Diderot has got to learn the language of size in self-defence,
because no society is safe in the hands of its clever people. . . .

The first men who dwelt in cities were talking animals. The man of
the machine age is a calculating animal. We live in a welter of figures:
cookery recipes, railway time-tables, unemployment aggregates, fines,
taxes, war debts, overtime schedules, speed limits, bowling averages,
betting odds, billiard scores, calories, babies' weights, clinical temperatures,
rainfall, hours of sunshine, motoring records, power indices, gas-meter
readings, bank rates, freight rates, death rates, discount, interest, lotteries,
wave lengths, and tyre pressures. Every night, when he winds up his
watch, the modern man adjusts a scientific instrument of a precision and
delicacy unimaginable to the most cunning artificers of Alexandria in its
prime. So much is commonplace. What escapes our notice is that in doing
these things we have learnt to use devices which presented tremendous
difficulties to the most brilliant mathematicians of antiquity. Ratios, limits,
acceleration, are not remote abstractions, dimly apprehended by the
solitary genius. They are photographed upon every page of our existence.
We have no difficulty in answering questions which tortured the minds
of very clever mathematicians in ancient times. This is not because you

MATHEMATICS, THE MIRROR OF CIVILIZATION 157

and I are very clever people. It is because we inherit a social culture which
has suffered the impact of material forces foreign to the intellectual life
of the ancient world. The most brilliant intellect is a prisoner within its
own social inheritance.

An illustration will help to make this quite definite at the outset. The
Eleatic philosopher Zeno set all his contemporaries guessing by propound-
ing a series of conundrums, of which the one most often quoted is the
paradox of Achilles and the tortoise. Here is the problem about which
the inventors of school geometry argued till they had speaker's throat and
writer's cramp. Achilles runs a race with the tortoise. He runs ten times
as fast as the tortoise. The tortoise has 100 yards' start. Now, says Zeno,
Achilles runs 100 yards and reaches the place where the tortoise started.
Meanwhile the tortoise has gone a tenth as far as Achilles, and is therefore
10 yards ahead of Achilles. Achilles runs this 10 yards. Meanwhile the
tortoise has run a tenth as far as Achilles, and is therefore i yard in front
of him. Achilles runs this i yard. Meanwhile the tortoise has run a tenth
of a yard and is therefore a tenth of a yard in front of Achilles. Achilles
runs this tenth of a yard. Meanwhile the tortoise goes a tenth of a tenth
of a yard. He is now a hundredth of a yard in front of Achilles. When
Achilles has caught up this hundredth of a yard, the tortoise is a thou-
sandth of a yard in front. So, argued Zeno, Achilles is always getting
nearer the tortoise, but can never quite catch him up.

You must not imagine that Zeno and all the wise men who argued the
point failed to recognize that Achilles really did get past the tortoise.
What troubled them was, where is the catch? You may have been asking
the same question. The important point is that you did not ask it for the
same reason which prompted them. What is worrying you is why they
thought up funny little riddles of that sort. Indeed, what you are really
concerned with is an historical problem. I am going to show you in a
minute that the problem is not one which presents any mathematical
difficulty to you. You know how to translate it into size language, because
you inherit a social culture which is separated from theirs by the collapse
of two great civilizations and by two great social revolutions. The
difficulty of the ancients was not an historical difficulty. It was a mathe-
matical difficulty. They had not evolved a size language into which this
problem could be freely translated.

The Greeks were not accustomed to speed limits and passenger-luggage
allowances. They found any problem involving division very much more
difficult than a problem involving multiplication. They had no way of
doing division to any order of accuracy, because they relied for calculation
on the mechanical aid of the counting frame or abacus. They could no^

158 MATTER, ENERGY, PHYSICAL LAW

do sums on paper. For all these and other reasons which we shall meet
again and again, the Greek mathematician was unable to see something
that we see without taking the trouble to worry about whether we see
it or not. If we go on piling up bigger and bigger quantities, the pile goes
on growing more rapidly without any end as long as we go on adding
more. If we can go on adding larger and larger quantities indefinitely
without coming to a stop, it seemed to Zeno's contemporaries that we
ought to be able to go on adding smaller and still smaller quantities
indefinitely without reaching a limit. They thought that in one case the
pile goes on for ever, growing more rapidly, and in the other it goes on
for ever, growing more slowly. There was nothing in their number
language to suggest that when the engine slows beyond a certain point,
it chokes off.

To see this clearly we will first put down in numbers the distance which
the tortoise traverses at different stages of the race after Achilles starts.
As we have described it above, the tortoise moves 10 yards in stage i,
i yard in stage 2, one-tenth of a yard in stage 3, one-hundredth of a yard
in stage 4, etc. Suppose we had a number language like the Greeks and
Romans, or the Hebrews, who used letters of the alphabet. Using the one
that is familiar to us because it is still used for clocks, graveyards, and
law-courts, we might write the total of all the distances the tortoise ran
before Achilles caught him up like this:

X + I + TT + -77 + 77 and so on.
ACM

We have put "and so on" because the ancient peoples got into great
difficulties when they had to handle numbers more than a few thousands.
Apart from the fact that we have left the tail of the series to your imagi-
nation (and do not forget that the tail is most of the animal if it goes on
for ever), notice another disadvantage about this script. There is absolutely
nothing to suggest to you how the distances at each stage of the race are
connected with one another. Today we have a number vocabulary which
makes this relation perfectly evident, when we write it down as:

i i i i i i

10 + i H 1 1 1 1 1 and so on.

10 100 1,000 10,000 100,000 1,000,000

In this case we put "and so on" to save ourselves trouble, not because
we have not the right number-words. These number-words were bor-
rowed from the Hindus, who learnt to write number language after
Zeno and Euclid had gone to their graves. A social revolution, the

MATHEMATICS, THE MIRROR OF CIVILIZATION 159

Protestant Reformation, gave us schools which made this number
language the common property of mankind. A second social upheaval,
the French Revolution, taught us to use a reformed spelling. Thanks
to the Education Acts of the nineteenth century, this reformed spelling
is part of the common fund of knowledge shared by almost every sane
individual in the English-speaking world. Let us write the last total,
using this reformed spelling, which we call decimal notation. That is to
say:

10 + i + o-i + o-oi + o-ooi + o-oooi + o-ooooi + ooooooi and so on.

We have only to use the reformed spelling to remind ourselves that this
can be put in a more snappy form :

iriiiiii etc.,
or still better:

ii'i.

We recognize the fraction o-i as a quantity that is less than -ny and more
than -fa. If we have not forgotten the arithmetic we learned at school, we
may even remember that o-i corresponds with the fraction %. This means
that, the longer we make the sum, o-i + o-oi 4- o-ooi, etc., the nearer it
gets to £, and it never grows bigger than £. The total of all the yards
the tortoise moves till there is no distance between himself and Achilles
makes up just ii£ yards, and no more.

You will now begin to see what was meant by saying that the riddle
presents no mathematical difficulty to you. You have a number language
constructed so that it can take into account a possibility which mathema-
ticians describe by a very impressive name. They call it the convergence
of an infinite series to a limiting value. Put in plain words, this only
means that, if you go on piling up smaller and smaller quantities as long
as you can, you may get a pile of which the size is not made measurably
larger by adding any more. The immense difficulty which the mathema-
ticians of the ancient world experienced when they dealt with a process
of division carried on indefinitely, or with what modern mathematicians
call infinite series, limits, transcendental numbers, irrational quantities,
and so forth, provides an example of a great social truth borne out by
the whole history of human knowledge. Fruitful intellectual activity of
the cleverest people draws its strength from the common knowledge
which all of us share. Beyond a certain point clever people can never
transcend the limitations of the social culture they inherit. When clever
people pride themselves on their own isolation, we may well wonder
whether they are very clever after all. Our studies in mathematics are

160 MATTER, ENERGY, PHYSICAL LAW

going to show us that whenever the culture of a people loses contact
with the common life of mankind and becomes exclusively the plaything
of a leisure class, it is becoming a priestcraft. It is destined to end, as does
all priestcraft, in superstition. To be proud of intellectual isolation from
the common life of mankind and to be disdainful of the great social task
of education is as stupid as it is wicked. It is the end of progress in knowl-
edge. History shows that superstitions are not manufactured by the plain
man. They are invented by neurotic intellectuals with too little to do.
The mathematician and the plain man each need one another. Maybe the
Western world is about to be plunged irrevocably into barbarism. If it
escapes this fate, the men and women of the leisure state which is now
within our grasp will regard the democratization of mathematics as a
decisive step in the advance of civilization.

In such a time as ours the danger of retreat into barbarism is very real.
We may apply to mathematics the words in which Cobbett explained the
uses of grammar to the working men of his own day when there was no
public system of free schools. In the first of his letters on English gram-
mar for a working boy, Cobbett wrote these words: "But, to the acquiring
of this branch of knowledge, my dear son, there is one motive, which,
though it ought, at all times, to be strongly felt, ought, at the present
time, to be so felt in an extraordinary degree. I mean that desire which
every man, and especially every young man, should entertain to be able
to assert with effect the rights and liberties of his country. When you
come to read the history of those Laws of England by which the freedom
of the people has been secured . . . you will find that tyranny has no
enemy so formidable as the pen. And, while you will see with exultation
the long-imprisoned, the heavily-fined, the banished William Prynne,
returning to liberty, borne by the people from Southampton to London,
over a road strewed with flowers: then accusing, bringing to trial and to
the block, the tyrants from whose hands he and his country had unjustly
and cruelly suffered; while your heart and the heart of every young man
in the kingdom will bound with joy at the spectacle, you ought all to bear
in mind, that, without a knowledge of grammar, Mr. Prynne could
never have performed any of those acts by which his name has been
thus preserved, and which have caused his name to be held in honour."

Today economic tyranny has no more powerful friend than the cal-
culating prodigy. Without a knowledge of mathematics, the grammar
of size and order, we cannot plan the rational society in which there will
be leisure for all and poverty for none. If we are inclined to be a little
afraid of the prospect, our first step towards understanding this grammar
is to realize that the reasons which repel many people from studying

MATHEMATICS, THE MIRROR OF CIVILIZATION 161

it are not at all discreditable. As mathematics has been taught and
expounded in schools no effort is made to show its social history, its
significance in our own social lives, the immense dependence of civilized
mankind upon it. Neither as children nor as adults are we told how the
knowledge of this grammar has been used again and again throughout
history to assist in the liberation of mankind from superstition. We are
not shown how it may be used by us to defend the liberties of the people.
Let us see why this is so.

The educational system of North- Western Europe was largely moulded
by three independent factors in the period of the Reformation. One was
linguistic in the ordinary sense. To weaken the power of the Church as
an economic overlord it was necessary to destroy the influence of the
Church on the imagination of the people. The Protestant Reformers
appealed to the recognized authority of scripture to show that the priestly
practices were innovations. They had to make the scriptures an open book.
The invention of printing was the mechanical instrument which destroyed
the intellectual power of the Pope. Instruction in Latin and Greek was
a corollary of the doctrine of the open bible. This prompted the great
educational innovation of John Knox and abetted the more parsimonious
founding of grammar schools in England. The ideological front against
popery and the wealthy monasteries strengthened its strategic position by
new translations and critical inspection of the scriptural texts. That is one
reason why classical scholarship occupied a place of high honour in the
educational system of the middle classes.

The language of size owes its position in Western education to two dif-
ferent social influences. While revolt against the authority of the Church
was gathering force, and before the reformed doctrine had begun to have
a wide appeal for the merchants and craftsmen of the medieval boroughs,
the mercantile needs of the Hansa had already led to the founding of
special schools in Germany for the teaching of the new arithmetic which
Europe had borrowed from the Arabs. An astonishing proportion of the
books printed in the three years after the first press was set up were com-
mercial arithmetics. Luther vindicated the four merchant gospels of
addition, subtraction, multiplication, and division with astute political
sagacity when he announced the outlandish doctrine that every boy should
be taught to calculate. The grammar of numbers was chained down to
commercial uses before people could foresee the vast variety of ways in
which it was about to invade man's social life.

Geometry, already divorced from the art of calculation, did not enter
into Western education by the same route. Apart from the stimulus which
the study of dead languages received from the manufacture of bibles,

162 MATTER, ENERGY, PHYSICAL LAW

classical pursuits were encouraged because the political theories of the
Greek philosophers were congenial to the merchants who were aspiring to
a limited urban democracy. The appeal of the city-state democracy to the
imagination of the wealthier bourgeois lasted till after the French Revolu-
tion, when it was laid to rest in the familiar funeral urns of mural decora-
tion. The leisure class of the Greek city-states played with geometry as
people play with crossword puzzles and chess today. Plato taught that
geometry was the highest exercise to which human leisure could be
devoted. So geometry became included in European education as a part of
classical scholarship, without any clear connection with the contemporary
reality of measuring Drake's "world encompassed." Those who taught
Euclid did not understand its social use, and generations of schoolboys
have studied Euclid without being told how a later geometry, which
grew out of Euclid's teaching in the busy life of Alexandria, made it
possible to measure the size of the world. Those measurements blew up
the pagan Pantheon of star gods and blazed the trail for the great naviga-
tions. The revelation of how much of the surface of our world was still
unexplored was the solid ground for what we call the faith of Columbus.
Plato's exaltation of mathematics as an august and mysterious ritual had
its roots in dark superstitions which troubled, and fanciful puerilities
which entranced, people who were living through the childhood of
civilization, when even the cleverest people could not clearly distinguish
the difference between saying that 13 is a "prime" number and saying
that 13 is an unlucky number. His influence on education has spread a veil
of mystery over mathematics and helped to preserve the queer freemasonry
of the Pythagorean brotherhoods, whose members were put to death for
revealing mathematical secrets now printed in school books. It reflects
no discredit on anybody if this veil of mystery makes the subject distaste-
ful. Plato's great achievement was to invent a religion which satisfies the
emotional needs of people who are out of harmony with their social
environment, and just too intelligent or too individualistic to seek
sanctuary in the cruder forms of animism. The curiosity of the men who
first speculated about atoms, studied the properties of the lodestone,
watched the result of rubbing amber, dissected animals, and catalogued
plants in the three centuries before Aristotle wrote his epitaph on Greek
science, had banished personalities from natural and familiar objects.
Plato placed animism beyond the reach of experimental exposure by
inventing a world of "universals." This world of universals was the world
as God knows it, the "real" world of which our own is but the shadow.
In this "real" world symbols of speech and number are invested with the

MATHEMATICS, THE MIRROR OF CIVILIZATION 163

magic which departed from the bodies of beasts and the trunks of trees
as soon as they were dissected and described. . . .

Two views are commonly held about mathematics. One comes from
Plato. This is that mathematical statements represent eternal truths. Plato's
doctrine was used by the German philosopher, Kant, as a stick with which
to beat the materialists of his time, when revolutionary writings like those
of Diderot were challenging priestcraft. Kant thought that the principles
of geometry were eternal, and that they were totally independent of our
sense organs. It happened that Kant wrote just before biologists dis-
covered that we have a sense organ, part of what is called the internal ear,
sensitive to the pull of gravitation. Since that discovery, the significance
of which was first fully recognized by the German physicist, Ernst Mach,
the geometry which Kant knew has been brought down to earth by
Einstein. It no longer dwells in the sky where Plato put it. We know
that geometrical statements when applied to the real world are only
approximate truths. The theory of Relativity has been very unsettling
to mathematicians, and it has now become a fashion to say that mathemat-
ics is only a game. Of course, this does not tell us anything about mathe-
matics. It only tells us something about the cultural limitations of some
mathematicians. When a man says that mathematics is a game, he is
making a private statement. He is telling us something about himself, his
own attitude to mathematics. He is not telling us anything about the
public meaning of a mathematical statement,

If mathematics is a game, there is no reason why people should play it
if they do not want to. With football, it belongs to those amusements
without which life would be endurable. The view which we explore is that
mathematics is the language of size, and that it is an essential part of the
equipment of an intelligent citizen to understand this language. If the
rules of mathematics are rules of grammar, there is no stupidity involved
when we fail to see that a mathematical truth is obvious. The rules of
ordinary grammar are not obvious. They have to be learned. They are not
eternal truths. They are conveniences without whose aid truths about
the sorts of things in the world cannot be communicated from one person
to another. In Cobbett's memorable words, Mr. Prynne would not have
been able to impeach Archbishop Laud if his command of grammar
had been insufficient to make himself understood. So it is with mathe-
matics, the grammar of size. The rules of mathematics are rules to be
learned. If they are formidable, they are formidable because they are
unfamiliar when you first meet them — like gerunds or nominative ab-
solutes. They are also formidable because in all languages there are so
many rules and words to memorize before we can read newspapers or

164 MATTER, ENERGY, PHYSICAL LAW

pick up radio news from foreign stations. Everybody knows that being
able to chatter in several foreign languages is not a sign of great social
intelligence. Neither is being able to chatter in the language of size. Real
social intelligence lies in the use of a language, in applying the right
words in the right context. It is important to know the language of size,
because entrusting the laws of human society, social statistics, population,
man's hereditary make-up, the balance of trade, to the isolated mathema-
tician without checking his conclusions is like letting a committee of
philologists manufacture the truths of human, animal, or plant anatomy
from the resources of their own imaginations.

. . . The language of mathematics differs from that of everyday life,
because it is essentially a rationally planned language. The languages
of size have no place for private sentiment, either of the individual or
of the nation. They are international languages like the binomial
nomenclature of natural history. In dealing with the immense com-
plexity of his social life man has not yet begun to apply inventiveness
to the rational planning of ordinary language when describing different
kinds of institutions and human behavior. The language of everyday
life is clogged with sentiment, and the science of human nature has
not advanced so far that we can describe individual sentiment in a
clear way. So constructive thought about human society is hampered
by the same conservatism as embarrassed the earlier naturalists. Nowa-
days people do not differ about what sort of animal is meant by Cimex or
Pediculus, because these words are only used by people who use them in
one way. They still can and often do mean a lot of different things when
they say that a mattress is infested with bugs or lice. The study of man's
social life has not yet brought forth a Linnaeus. So an argument about
the "withering away of the State" may disclose a difference about the
use of the dictionary when no real difference about the use of the police-
man is involved. Curiously enough, people who are most sensible about
the need for planning other social amenities in a reasonable way are often
slow to see the need for creating a rational and international language.

The technique of measurement and counting has followed the caravans
and galleys of the great trade routes. It has developed very slowly. At
least four thousand years intervened between the time when men could
calculate when the next eclipse would occur and the time when men could
calculate how much iron is present in the sun. Between the first recorded
observations of electricity produced by friction and the measurement of
the attraction of an electrified body two thousand years intervened. Per-
haps a longer period separates the knowledge of magnetic iron (or lode-
stone) and the measurement of magnetic force. Classifying things accord-

MATHEMATICS, THE MIRROR OF CIVILIZATION 165

ing to size has been a much harder task than recognizing the different sorts
of things there are. It has been more closely related to man's social achieve-
ments than to his biological equipment. Our eyes and ears can recognize
different sorts of things at a great distance. To measure things at a dis-
tance, man has had to make new sense organs for himself, like the
astrolabe, the telescope, and the microphone. He has made scales which
reveal differences of weight to which our hands are quite insensitive. At
each stage in the evolution of the tools of measurement man has refined
the tools of size language. As human inventiveness has turned from the
counting of flocks and seasons to the building of temples, from the build-
ing of temples to the steering of ships into chartless seas, from seafaring
plunder to machines driven by the forces of dead matter, new languages
of size have sprung up in succession. Civilizations have risen and fallen.
At each stage a more primitive, less sophisticated culture breaks through
the barriers of custom thought, brings fresh rules to the grammar of
measurement, bearing within itself the limitation of further growth and the
inevitability that it will be superseded in its turn. The history of mathe-
matics is the mirror of civilization.

The beginnings of a size language are to be found in the priestly
civilizations of Egypt and Sumeria. From these ancient civilizations we
see the first-fruits of secular knowledge radiated along the inland trade
routes to China and pushing out into and beyond the Mediterranean,
where the Semitic peoples are sending forth ships to trade in tin and dyes.
The more primitive northern invaders of Greece and Asia Minor collect
and absorb the secrets of the pyramid makers in cities where a priestly
caste is not yet established. As the Greeks become prosperous, geometry
becomes a plaything. Greek thought itself becomes corrupted with the
star worship of the ancient world. At the very point when it seems almost
inevitable that geometry will make way for a new language, it ceases to
develop further. The scene shifts to Alexandria, the greatest centre of ship-
ping and the mechanical arts in the ancient world. Men are thinking about
how much of the world remains to be explored. Geometry is applied to the
measurement of the heavens. Trigonometry takes its place. The size of the
earth, the distance of the sun and moon are measured. The star gods are
degraded. In the intellectual life of Alexandria, the factory of world
religions, the old syncretism has lost its credibility. It may still welcome
a god beyond the sky. It is losing faith in the gods within the sky.

In Alexandria, where the new language of star measurement has its
beginnings, men are thinking about numbers unimaginably large
compared with the numbers which the Greek intellect could grasp.
Anaxagoras had shocked the court of Pericles by declaring that the sun

166 MATTER, ENERGY, PHYSICAL LAW

was as immense as the mainland of Greece, Now Greece itself had sunk
into insignificance beside the world of which Eratosthenes and Poseidonius
had measured the circumference. The world itself sank into insignifi-
cance beside the sun as Aristarchus had measured it. Ere the dark night of
monkish superstition engulfed the great cosmopolis of antiquity, men were
groping for new means of calculation. The bars of the counting frame had
become the bars of a cage in which the intellectual life of Alexandria was
imprisoned. Men like Diophantus and Theon were using geometrical
diagrams to devise crude recipes for calculation. They had almost invented
the third new language of algebra. That they did not succeed was the
nemesis of the social culture they inherited. In the East the Hindus had
started from a much lower level. Without the incubus of an old-established
vocabulary of number, they had fashioned new symbols which lent them-
selves to simple calculation without mechanical aids. The Moslem civiliza-
tion which swept across the southern domain of the Roman Empire
brought together the technique of measurement, as it had evolved in the
hands of the Greeks and the Alexandrians, adding the new instrument
for handling numbers which was developed through the invention of the
Hindu number symbols. In the hands of Arabic mathematicians like Omar
Khayyam, the main features of a language of calculation took shape. We
still call it by the Arabic name, algebra. We owe algebra and the pattern
of modern European poetry to a non-Aryan people who would be excluded
from the vote in the Union of South Africa.

Along the trade routes this new arithmetic is brought into Europe
by Jewish scholars from the Moorish universities of Spain and by Gentile
merchants trading with the Levant, some of them patronized by nobles
whose outlook had been unintentionally broadened by the Crusades.
Europe stands on the threshold of the great navigations. Seafarers are
carrying Jewish astronomers who can use the star almanacs which Arab
scholarship had prepared. The merchants are becoming rich. More than
ever the world is thinking in large numbers. The new arithmetic or
"algorithm" sponsors an amazing device which was prompted by the need
for more accurate tables of star measurement for use in seafaring. Loga-
rithms were among the cultural first-fruits of the great navigations. Mathe-
maticians are thinking in maps, in latitude and longitude. A new kind
of geometry (what we call graphs in everyday speech) was an inevitable
consequence. This new geometry of Descartes contains something which
Greek geometry had left out. In the leisurely world of antiquity there were
no clocks. In the bustling world of the great navigations mechanical
clocks are displacing the ancient ceremonial function of the priesthood as
timekeepers. A geometry which could represent time and a religion in

MATHEMATICS, THE MIRROR OF CIVILIZATION 167

which there were no saints' days are emerging from the same social
context. From this geometry of time a group of men who were studying
the mechanics of the pendulum clock and making fresh discoveries about
the motion of the planets devised a new size language to measure motion.
Today we call it "the" calculus.

This crude outline of the history of mathematics as a mirror of civiliza-
tion, interlocking with man's common culture, his inventions, his economic
arrangements, his religious beliefs, may be left at the stage which had been
reached when Newton died. What has happened since has been largely
the filling of gaps, the sharpening of instruments already devised. Here
and there are indications of a new sort of mathematics. We see a hint of
it in social statistics and the study of the atom. We begin to see possi-
bilities of new languages of size transcending those we now use, as the
calculus of movement gathered into itself all that had gone before.

1937

Experiments and Ideas

BENJAMIN FRANKLIN

THE KITE

As frequent mention is made in public papers from Europe of the
success of the Philadelphia experiment for drawing the electric fire from
clouds by means of pointed rods of iron erected on high buildings, &, it
may be agreeable to the curious to be informed, that the same experi-
ment has succeeded in Philadelphia, though made in a different and
more easy manner, which is as follows:

Make a small cross of two light strips of cedar, the arms so long as to
reach to the four corners of a large thin silk handkerchief when extended;
tie the corners of the handkerchief to the extremities of the cross, so you
have the body of a kite; which being properly accommodated with a
tail, loop, and string, will rise in the air, like those made of paper; but
this being of silk, is fitter to bear the wet and wind of a thunder-gust
without tearing. To the top of the upright stick of the cross is to be fixed
a very sharp pointed wire, rising a foot or more above the wood. To
the end of the twine, next the hand, is to be tied a silk ribbon, and where
the silk and twine join, a key may be fastened. This kite is to be raised
when a thunder-gust appears to be coming on, and the person who holds
the string must stand within a door or window or under some cover,
so that the silk ribbon may not be wet; and care must be taken that the
twine does not touch the frame of the door or window. As soon as any of
the thunder-clouds come over the kite, the pointed wire will draw the
electric fire from them, and the kite, with all the twine, will be electrified,
and the loose filaments of the twine will stand out every way, and be
attracted by an approaching finger. And when the rain has wet the kite
and twine, so that it can conduct the electric fire freely, you will find it
stream out plentifully from the key on the approach of your knuckle.
At this key the phial may charged; and from electric fire thus obtained,
spirits may be kindled, and all the other electric experiments be per-

168

EXPERIMENTS AND IDEAS 169

formed, which are usually done by the help of a rubbed glass globe or
tube, and thereby the sameness of the electric matter with that of lightning
completely demonstrated. Letter to Peter Collinson, 1752

ELECTRICAL EXPERIMENTS AND ELECTROCUTION

Your question, how I came first to think of proposing the experiment
of drawing down the lightning, in order to ascertain its sameness with
the electric fluid, I cannot answer better than by giving you an extract
from the minutes I used to keep of the experiments I made, with
memorandums of such as I purposed to make, the reasons for making
them, and the observations that arose upon them, from which minutes my
letters were afterwards drawn. By this extract you will see, that the
thought was not so much "an out-of-the-way one," but that it might
have occurred to any electrician.

"November 7, 1749. Electrical fluid agrees with lightning in these par-
ticulars, i. Giving light. 2. Colour of the light. 3. Crooked direction.
4. Swift motion. 5. Being conducted by metals. 6. Crack or noise in explod-
ing. 7. Subsisting in water or ice. 8. Rending bodies it passes through.
9. Destroying animals. 10. Melting metals, n. Firing inflammable sub-
stances. 12. Sulphureous smell. The electric fluid is attracted by points.
We do not know whether this property is in lightning. But since they
agree in all particulars wherein we can already compare them, is it not
probable they agree likewise in this ? Let the experiment be made." . . „

The knocking down of the six men was performed with two of my
large jarrs not fully charged. I laid one end of my discharging rod upon
the head of the first; he laid his hand on the head of the second; the
second his hand on the head of the third, and so to the last, who held,
in his hand, the chain that was connected with the outside of the jarrs.
When they were thus placed, I applied the other end of my rod to the
prime-conductor, and they all dropt together. When they got up, they all
declared they had not felt any stroke, and wondered how they came to
fall; nor did any of them either hear the crack, or see the light of it.
You suppose it a dangerous experiment; but I had once suffered the same
myself, receiving, by accident, an equal stroke through my head, that
struck me down, without hurting me: And I had seen a young woman,
that was about to be electrified through the feet, (for some indisposition)
receive a greater charge through the head, by inadvertently stooping for-
ward to look at the placing of her feet, till her forhead (as she was very
tall) came too near my prime-conductor: she dropt, but instantly got up

170 MATTER, ENERGY, PHYSICAL LAW

again, complaining o£ nothing. A person so struck, sinks down doubled,
or folded together as it were, the joints losing their strength and stiffness
at once, so that he drops on the spot where he stood, instantly, and there
is no previous staggering, nor does he ever fall lengthwise. Too great a
charge might, indeed, kill a man, but I have not yet seen any hurt done
by it. It would certainly, as you observe, be the easiest of all deaths. . . -

Letter to John Lining, 7755

ORIGIN OF NORTHEAST STORMS

Agreeable to your request, I send you my reasons for thinking that our
northeast storms in North America begin first, in point of time, in the
southwest parts: That is to say, the air in Georgia, the farthest of our
colonies to the Southwest, begins to move southwesterly before the air
of Carolina, which is the next colony northeastward; the air of Carolina
has the same motion before the air of Virginia, which lies still more
northeastward; and so on northeasterly through Pennsylvania, New-York,
New-England, &c., quite to Newfoundland.

These northeast storms are generally very violent, continue sometimes
two or three days, and often do considerable damage in the harbours
along the coast. They are attended with thick clouds and rain.

What first gave me this idea, was the following circumstance. About
twenty years ago, a few more or less, I cannot from my memory be cer-
tain, we were to have an eclipse of the moon at Philadelphia, on a Fri-
day evening, about nine o'clock. I intended to observe it, but was pre-
vented by a northeast storm, which came on about seven, with thick
clouds as usual, that quite obscured the whole hemisphere. Yet when the
post brought us the Boston newspaper, giving an account of the effects
of the same storm in those parts, I found the beginning of the eclipse
had been well observed there, though Boston lies N. E. of Philadelphia
about 400 miles. This puzzled me because the storm began with us so
soon as to prevent any observation, and being a N. E. storm, I imagined
it must have begun rather sooner in places farther to the northeastward
than it did at Philadelphia. I therefore mentioned it in a letter to my
brother, who lived at Boston; and he informed me the storm did not
begin with them till near eleven o'clock, so that they had a good observa-
tion of the eclipse: And upon comparing all the other accounts I received
from the several colonies, of the time of beginning of the same storm, and,
since that of other storms of the same kind, 1^ found the beginning to
be always later the farther northeastward. I have not my notes with me

EXPERIMENTS AND IDEAS 171

here in England, and cannot, from memory, say the proportion o£ time
to distance, but I think it is about an hour to every hundred miles.

From thence I formed an idea of the cause of these storms, which I
would explain by a familiar instance or two. Suppose a long canal of
water stopp'd at the end by a gate. The water is quite at rest till the
gate is open, then it begins to move out through the gate; the water next
the gate is first in motion, and moves towards the gate; the water next
to that first water moves next, and so on successively, till the water at
the head of the canal is in motion, which is last of all. In this case all the
water moves indeed towards the gate, but the successive times of begin-
ning motion are the contrary way, viz. from the gate backwards to the
head of the canal. Again, suppose the air in a chamber at rest, no cur-
rent through the room till you make a fire in the chimney. Immediately
the air in the chimney, being rarefied by the fire, rises; the air next the
chimney flows in to supply its place, moving towards the chimney; and,
in consequence, the rest of the air successively, quite back to the door.
Thus to produce our northeast storms, I suppose some great heat and
rarefaction of the air in or about the Gulph of Mexico; the air thence
rising has its place supplied by the next more northern, cooler, and there-
fore denser and heavier, air; that, being in motion, is followed by the
next more northern air, &c. &c., in a successive current, to which current
our coast and inland ridge of mountains give the direction of northeast,
as they lie N.E. and S.W. Letter to Alexander Small, 1760

A PROPHECY OF AERIAL INVASION

I have this day received your favor of the 2d inst. Every information
in my power, respecting the balloons, I sent you just before Christmas,
contained in copies of my letters to Sir Joseph Banks. There is no secret
in the affair, and I make no doubt that a person coming from you would
easily obtain a sight of the different balloons of Montgolfier and Charles,
with all the instructions wanted; and, if you undertake to make one,
I think it extremely proper and necessary to send an ingenious man here
for that purpose; otherwise, for want of attention to some particular cir-
cumstance, or of not being acquainted with it, the experiment might mis-
carry, which, in an affair of so much public expectation, would have
bad consequences, draw upon you a great deal of censure, and affect your
reputation. It is a serious thing to draw out from their affairs all the
inhabitants of a great city and its environs, and a disappointment makes
them angry. At Bourdeaux lately a person who pretended to send up a
balloon, and had received money from many people, not being able to

172 MATTER, ENERGY, PHYSICAL LAW

make it rise, the populace were so exasperated that they pulled down his
house and had like to have killed him.

It appears, as you observe, to be a discovery of great importance, and
what may possibly give a new turn to human affairs. Convincing
sovereigns of the folly of wars may perhaps be one effect of it; since it will
be impracticable for the most potent of them to guard his dominions.
Five thousand balloons, capable of raising two men each, could not cost
more than five ships of the line; and where is the prince who can afford
so to cover his country with troops for its defence, as that ten thousand
men descending from the clouds might not in many places do an infi-
nite deal of mischief, before a force could be brought together to repel
them? , . . Letter to Jan Ingcnhousz, 1784

DAYLIGHT SAVING

You often entertain us with accounts of new discoveries. Permit me to
communicate to the public, through your paper, one that has lately been
made by myself, and which I conceive may be of great utility.

I was the other evening in a grand company, where the new lamp of
Messrs. Quinquet and Lange was introduced, and much admired for its
splendour; but a general inquiry was made, whether the oil it consumed
was not in proportion to the light it afforded, in which case there would
be no saving in the use of it. No one present could satisfy us in that
point, which all agreed ought to be known, it being a very desirable
thing to lessen, if possible, the expense of lighting our apartments, when
every other article of family expense was so much augmented.

I was pleased to see this general concern for economy, for I love economy
exceedingly.

I went home, and to bed, three or four hours after midnight, with my
head full of the subject. An accidental sudden noise waked me about six
in the morning, when I was surprised to find my room filled with light;
and I imagined at first, that a number of those lamps had been brought
into it; but, rubbing my eyes, I perceived the light came in at the win-
dows. I got up and looked out to see what might be the occasion of it,
when I saw the sun just rising above the horizon, from where he poured
his rays plentifully into my chamber, my domestic having negligently
omitted, the preceding evening, to close the shutters.

I looked at my watch, which goes very well, and found that it was but
six o'clock; and still thinking it something extraordinary that the sun
should rise so early, I looked into the almanac, where I found it to be the
hour given for his rising on that day. I looked forward, too, and found he

EXPERIMENTS AND IDEAS 173

was to rise still earlier every day till towards the end of June; and that
at no time in the year he retarded his rising so long as till eight o'clock.
Your readers, who with me have never seen any signs of sunshine before
noon, and seldom regard the astronomical part of the almanac, will be as
much astonished as I was, when they hear of his rising so early; and
especially when I assure them, that he gives light as soon as he rises. I
am convinced of this. I am certain of my fact. One cannot be more
certain of any fact. I saw it with my own eyes. And, having repeated
this observation the three following mornings, I found always precisely
the same result. . . .

This event has given rise in my mind to several serious and important
reflections. I considered that, if I had not been awakened so early in the
morning, I should have slept six hours longer by the light of the sun,
and in exchange have lived six hours the following night by candle-
light; and, the latter being a much more expensive light than the former,
my love of economy induced me to muster up what little arithmetic I was
master of, and to make some calculations, which I shall give you, after
observing that utility is, in my opinion the test of value in matters of
invention, and that a discovery which can be applied to no use, or is not
good for something, is good for nothing.

I took for the basis of my calculation the supposition that there are one
hundred thousand families in Paris, and that these families consume in
the night half a pound of bougies, or candles, per hour. I think this is a
moderate allowance, taking one family with another; for though, I believe
some consume less, I know that many consume a great deal more. Then
estimating seven hours per day as the medium quantity between the
time of the sun's rising and ours, he rising during the six following
months from six to eight hours before noon, and there being seven hours
of course per night in which we burn candles, the account will stand
thus; —

In the six months between the 20th of March and the 2oth of September,
there are

Nights 183

Hours of each night in which we burn candles 7

Multiplication gives for the total number of hours 1,281

These 1,281 hours multiplied by 100,000, the number of

inhabitants, give 128,100,000

One hundred twenty-eight millions and one hundred thousand
hours, spent at Paris by candle-light, which, at half a pound
of wax and tallow per hour, gives the weight of 64,050,000

174 MATTER, ENERGY, PHYSICAL LAW

Sixty-four millions and fifty thousand of pounds, which, esti-
mating the whole at the medium price of thirty sols the
pound, makes the sum of ninety-six millions and seventy-
five thousand livres tournois 96,075,000

An immense sum! that the city of Paris might save every year, by the
economy of using sunshine instead of candles. . . .

Letter to the Authors of "The Journal of Paris," 1784

BIFOCALS

By Mr. Dollond's saying, that my double spectacles can only serve par-
ticular eyes, I doubt he has not been rightly informed of their construc-
tion. I imagine it will be found pretty generally true, that the same
convexity of glass, through which a man sees clearest and best at the
distance proper for reading, is not the best for greater distances. I there-
fore had formerly two pair of spectacles, which I shifted occasionally, as
in travelling I sometimes read, and often wanted to regard the prospects.
Finding this change troublesome, and not always sufficiently ready, I had
the glasses cut, and half of each kind associated in the same circle. . . .

By this means, as I wear my spectacles constantly, I have only to move
my eyes up or down, as I want to see distinctly far or near, the proper
glasses being always ready. This I find more particularly convenient since
my being in France, the glasses that serve me best at table to see what
I eat, not being the best to see the faces of those on the other side of the
table who speak to me; and when one's ears are not well accustomed to
the sounds of a language, a sight of the movements in the features of him
that speaks helps to explain; so that I understand French better by the
help of my spectacles. Letter to George Whatley, 1785

Exploring the Atom

SIR JAMES JEANS

From The Universe Around Us

AS FAR BACK AS THE FIFTH CENTURY BEFORE CHRIST,
-£*» Greek philosophy was greatly exercised by the question of whether
in the last resort the ultimate substance of the universe was continuous or
discontinuous. We stand on the sea-shore, and all around us see stretches
of sand which appear at first to be continuous in structure, but which a
closer examination shews to consist of separate hard particles or grains.
In front rolls the ocean, which also appears at first to be continuous in
structure, and this we find we cannot divide into grains or particles, no
matter how we try. We can divide it into drops, but then each drop can
be subdivided into smaller drops, and there seems to be no reason, on the
face of things, why this process of subdivision should not be continued
for ever. The question which agitated the Greek philosophers was, in
effect, whether the water of the ocean or the sand of the sea-shore gave
the truest picture of the ultimate structure of the substance of the universe.

The "atomic" school, founded by Dernocritus, Leucippus and Lucretius,
believed in the ultimate discontinuity of matter; they taught that any
substance, after it had been subdivided a sufficient number of times, would
be found to consist of hard discrete particles which did not admit of
further subdivision. For them the sand gave a better picture of ultimate
structure than the water, because they thought that sufficient subdivision
would cause the water to display the granular properties of sand. And this
intuitional conjecture is amply confirmed by modern science.

The question is, in effect, settled as soon as a thin layer of a substance
is found to shew qualities essentially different from those of a slightly
thicker layer. A layer of yellow sand swept uniformly over a red floor
will make the whole floor appear yellow if there is enough sand to make
a layer at least one grain thick. If, however, there is only half this much
sand, the redness of the floor inevitably shews through; it is impossible
to spread sand in a uniform layer only half a grain thick. This abrupt

175

176 MATTER, ENERGY, PHYSICAL LAW

change in the properties of a layer o£ sand is of course a consequence of
the granular structure of sand.

Similar changes are found to occur in the properties of thin layers of
liquid. A teaspoonful of soup will cover the bottom of a soup plate, but a
single drop of soup will only make an untidy splash. In some cases it is
possible to measure the exact thickness of layer at which the properties
of liquids begin to change. In 1890 Lord Rayleigh found that thin films
of olive oil floating on water changed their properties entirely as soon as
the thickness of the film was reduced to below a millionth of a millimetre
(or a 25,ooo,oooth part of an inch). The obvious interpretation, which is
confirmed in innumerable ways, is that olive oil consists of discrete
particles — analogous to the "grains" in a pile of sand — each having a
diameter somewhere in the neighbourhood of a 25,ooo,oooth part of an
inch.

Every substance consists of such "grains"; they are called molecules.
The familiar properties of matter are those of layers many molecules
thick; the properties of layers less than a single molecule thick are known
only to the physicist in his laboratory.

MOLECULES

How are we to break up a piece of substance into its ultimate grains,
or molecules? It is easy for the scientist to say that, by subdividing water
for long enough, we shall come to grains which cannot be subdivided any
further; the plain man would like to see it done.

Fortunately the process is one of extreme simplicity. Take a glass of
water, apply gentle heat underneath, and the water begins to evaporate.
What does this mean? It means that the water is being broken up into
its separate ultimate grains or molecules. If the glass of water could be
placed on a sufficiently sensitive spring balance, we should see that the
process of evaporation does not proceed continuously, layer after layer,
but jerkily, moleciile by molecule. We should find the weight of the
water changing by jumps, each jump representing the weight of a single
molecule. The glass may contain any integral number of molecules but
never fractional numbers — if fractions of a molecule exist, at any rate
they do not come into play in the evaporation of a glass of water.

THE GASEOUS STATE. The molecules which break loose from the surface
of the water as it evaporates form a gas — water-vapour or steam. A gas
consists of a vast number of molecules which fly about entirely independ-
ently of one another, except at the rare instants at which two collide,
and so interfere with each other's motion. The extent to which the mole-
cules interfere with one another must obviously depend on their sizes;

EXPLORING THE ATOM 177

the larger they are, the more frequent their collisions will be, and the
more they will interfere with one another's motion. Actually the extent
of this interference provides the best means of estimating the sizes of
molecules. They prove to be exceedingly small, being for the most part
about a hundred-millionth of an inch in diameter, and, as a general rule,
the simpler molecules have the smaller diameters, as we might perhaps
have anticipated. The molecule of water has a diameter of 1.8 hundred-
millionths of an inch (4.6 X io~8 cm.), while that of the simpler hydro-
gen molecule is only just over a hundred-millionth of an inch (2.7 X
io"8 cm.). The fact that a number of different lines of investigation all
assign the same diameters to these molecules provides an excellent proof
of the reality of their existence.

As molecules are so exceedingly small, they must also be exceedingly
numerous. A pint of water contains 1.89 X io25 molecules, each weighing
i. 06 X io~24 ounce. If these molecules were placed end to end, they
would form a chain capable of encircling the earth over 200 million times.
If they were scattered over the whole land surface of the earth, there
would be nearly 100 million molecules to every square inch of land. If
we think of the molecules as tiny seeds, the total amount of seed needed
to sow the whole earth at the rate of 100 million molecules to the square
inch could be put into a pint pot.

These molecules move with very high speeds; the molecules which
constitute the ordinary air of an ordinary room move with an average
speed of about 500 yards a second. This is roughly the speed of a rifle-
bullet, and is rather more than the ordinary speed of sound. As we are
familiar with this latter speed from everyday experience, it is easy to form
some conception of molecular speeds in a gas. It is not a mere accident
that molecular speeds are comparable with the speed of sound. Sound
is a disturbance which one molecule passes on to another when it collides
with it, rather like relays of messengers passing a message on to one
another, or Greek torch-bearers handing on their lights. Between collisions
the message is carried forward at exactly the speed at which the molecules
travel. If these all travelled with precisely the same speed and in precisely
the same direction, the sound would of course travel with just the speed
of the molecules. But many of them travel on oblique courses, so that
although the average speed of individual molecules in ordinary air is
about 500 yards a second, the net forward velocity of the sound is only
about 370 yards a second.

At high temperatures the molecules may have even greater speeds; the
molecules of steam in a boiler may move at 1000 yards a second.

It is the high speed of molecular motion that is responsible for the

178 MATTER, ENERGY, PHYSICAL LAW

great pressure exerted by a gas; any surface in contact with ordinary air
is exposed to a hail of molecules each moving with the speed of a rifle-
bullet. With each breath we take, swarms of millions of millions of
millions of molecules enter our bodies, each moving at about 500 yards a
second, and nothing but their incessant hammering on the walls of our
lungs keeps our chests from collapsing. To take another instance, the
piston in a locomotive cylinder is bombarded by about 14 X io28 mole-
cules every second, each moving at about 800 yards a second. This inces-
sant fusillade of innumerable tiny bullets urges the piston forward in the
cylinder, and so propels the train. . . .

ATOMS

In the gaseous state, each separate molecule retains all the chemical
properties of the solid or liquid substance from which it originated;
molecules of steam, for instance, moisten salt or sugar, or combine with
thirsty substances such as unslaked lime or potassium chloride, just as
water does.

Is it possible to break up the molecules still further? Lucretius and his
predecessors would, of course, have said: "No." A simple experiment,
which, however, was quite beyond their range, will speedily shew that
they were wrong.

On sliding the two wires of an ordinary electric bell circuit into a
tumbler of water, down opposite sides, bubbles of gas will be found to
collect on the wires, and chemical examination shews that the two lots of
gas have entirely different properties. They cannot, then, both be water-
vapour, and in point of fact neither of them is; one proves to be hydrogen
and the other oxygen. There is found to be twice as much hydrogen as
oxygen, whence we conclude that the electric current has broken up each
molecule of water into two parts of hydrogen and one of oxygen. These
smaller units into which a molecule is broken are called "atoms." Each
molecule of water consists of two atoms of hydrogen (H) and one atom
of oxygen (O) ; this is expressed in its chemical formula HbO.

All the innumerable substances which occur on earth — shoes, ships,
sealing-wax, cabbages, kings, carpenters, walruses, oysters, everything we
can think of — can be analysed into their constituent atoms, either in this
or in other ways. It might be thought that a quite incredible number of
different kinds of atoms would emerge from the rich variety of sub-
stances we find on earth. Actually the number is quite small. The same
atoms turn up again and again, and the great variety of substances we
find on earth results, not from any great variety of atoms entering into
their composition, but from the great variety of ways in which a few

EXPLORING THE ATOM 179

types of atoms can be combined — just as in a colour-print three colours
can be combined so as to form almost all the colours we meet in nature,
not to mention other weird hues such as never were on land or sea.

Analysis of all known terrestrial substances has, so far, revealed only
90 different kinds of atoms. Probably 92 exist, there being reasons for
thinking that two, or possibly even more, still remain to be discovered.
Even of the 90 already known, the majority are exceedingly rare, most
common substances being formed out of the combinations of about 14
different atoms, say hydrogen (H), carbon (C), nitrogen (N), oxygen
(O), sodium (Na), magnesium (Mg), aluminum (Al), silicon (Si),
phosphorus (P), sulphur (S), chlorine (Cl), potassium (K), calcium
(Ca), and iron (Fe).

In this way, the whole earth, with its endless diversity of substances, is
found to be a building built of standard bricks — the atoms. And of these
only a few types, about 14, occur at all abundantly in the structure, the
others appearing but rarely.

SPECTROSCOPY. Just as a bell struck with a hammer emits a char-
acteristic note, so every atom put in a flame or in an electric arc or discharge-
tube, emits a characteristic light, which the spectroscope will resolve into
its separate constituents.

The spectrum of sunlight discloses the chemical composition of the
solar atmosphere, and here again we still find the same types of atoms
as on earth, and no others. With a few quite unimportant exceptions,
every line in the sun's spectrum can be identified as originating from
some type of atom already known on earth. Of the fifteen metals which
are believed to be commonest in the sun's atmosphere, seven, which
account for no less than 96 per cent, of the whole, figure in our list of the
fourteen elements which are commonest on earth. Actually they are
precisely the seven principal constituents of terrestrial rocks, although
their relative proportions are different on the sun and earth.

Thus, broadly speaking the same atoms occur in the sun's atmosphere
as on earth, and the same is true of the atmospheres of the stars. It is
tempting to jump to the generalisation that the whole universe is built
solely of the 90 or 92 types of atoms found on earth, but at present there
is no justification for this. The light we receive from the sun and stars
comes only from the outermost layers of their surfaces, and so conveys no
information at all as to the types of atoms to be found in the stars'
interiors. Indeed we have no knowledge of the types of atoms which
occur in the interior of our own earth.

THE STRUCTURE OF THE ATOM. Until quite recently, atoms were
regarded as the permanent bricks of which the whole universe was built.

180 MATTER, ENERGY, .PHYSICAL LAW

All the changes of the universe were supposed to amount to nothing
more drastic than a re-arrangement of permanent indestructible atoms;
like a child's box of bricks, these built many buildings in turn. The story
of twentieth-century physics is primarily the story of the shattering of
this concept.

It was towards the end of the last century that Crookes, Lenard, and
above all, Sir J. J. Thomson first began to break up the atom. The struc-
tures which had been deemed the unbreakable bricks of the universe for
more than 2000 years, were suddenly shown to be very susceptible to
having fragments chipped off. A mile-stone was reached in 1897, when
Thomson shewed that these fragments were identical no matter what
type of atom they came from; they were of equal weight and they carried
equal charges of negative electricity. On account of this last property they
were called "electrons." The atom cannot, however, be built up of elec-
trons and nothing else, for as each electron carries a negative charge of
electricity, a structure which consisted of nothing but electrons would also
carry a negative charge. Two negative charges of electricity repel one
another, as also do two positive charges, while two charges, one of positive
and one of negative electricity, attract one another. This makes it easy
to determine whether any body or structure carries a positive or a negative
charge of electricity, or no charge at all. Observation shews that a com-
plete atom carries no charge at all, so that somewhere in the atom there
must be a positive charge of electricity, of amount just sufficient to
neutralise the combined negative charges of all the electrons.

In 1911 experiments by Sir Ernest Rutherford and others revealed the
architecture of the atom, in its main lines at least. As we shall soon see,
nature herself provides an endless supply of small particles charged with
positive electricity, and moving with very high speeds, in the a-particles
shot off from radio-active substances. Rutherford's method was in brief
to fire these into atoms and observe the result. And the surprising result
he obtained was that the vast majority of these bullets passed straight
through the atom as though it simply did not exist. It was like shooting
at a ghost.

Yet the atom was not all ghostly. A tiny fraction — perhaps one in
10,000 — of the bullets were deflected from their courses as if they had met
something very substantial indeed. A mathematical calculation shewed
that these obstacles could only be the missing positive charges of the
atoms.

A detailed study of the paths of these projectiles proved that the whole
positive charge of an atom must be concentrated in a single very small
space, having dimensions of the order of only a millionth of a millionth of

EXPLORING THE ATOM 181

an inch. In this way, Rutherford was led to propound the view of atomic
structure which is generally associated with his name. He supposed the
chemical properties and nature of the atom to reside in a weighty, but
excessively minute, central "nucleus" carrying a positive charge of elec-
tricity, around which a number of negatively charged electrons described
orbits. He had to suppose that the electrons were in motion in the atom,
otherwise the attraction of positive for negative electricity would immedi-
ately draw them into the central nucleus — just as gravitational attraction
would cause the earth to fall into the sun, were it not for the earth's
orbital motion. In brief, Rutherford supposed the atom to be constructed
like the solar system, the heavy central nucleus playing the part of the
sun and the electrons acting the parts of the planets.

The modern theory of wave-mechanics casts doubt on some at least
of these concepts — perhaps on all, although this is still in doubt. Thus it
may prove necessary ro discard many or all of them before long. Yet
Rutherford's concepts provide a simple and easily visualised picture of
the atom, whereas the theory of wave-mechanics has not yet been able
to provide a picture at all. For this reason we shall continue to describe
the atom in terms of Rutherford's picture.

According to this picture, the electrons are supposed to move round
the nucleus with just the speeds necessary to save them from being
drawn into it, and these speeds prove to be terrific, the average electron
revolving around its nucleus several thousand million million times every
second, with a speed of hundreds of miles a second. Thus the smallness
of their orbits does not prevent the electrons moving with higher orbital
speeds than the planets, or even the stars themselves.

By clearing a space around the central nucleus, and so preventing other
atoms from coming too near to it, these electronic orbits give size to the
atom. The volume of space kept clear by the electrons is enormously
greater than the total volume of the electrons; roughly, the ratio of
volumes is that of the battlefield to the bullets. The atom has about
100,000 times the diameter, and so about a thousand million million times
the volume, of a single electron. The nucleus, although it generally weighs
3000 or 4000 times as much as all the electrons in the atom together, is at
most comparable in size with, and may be even smaller than, a single
electron.

We know the extreme emptiness of astronomical space. Choose a point
in space at random, and the odds against its being occupied by a star are
enormous. Even the solar system consists overwhelmingly of empty space;
choose a spot inside the solar system at random, and there are still
immense odds against its being occupied by a planet or even by a comet,

182 MATTER, ENERGY, PHYSICAL LAW

meteorite or smaller body. And now we see that this emptiness extends
also to the space of physics. Even inside the atom we choose a point at
random, and the odds against there being anything there are immense;
they are of the order of at least millions of millions to one. Six specks
of dust inside Waterloo Station represent — or rather over-represent — the
extent to which space is crowded with stars. In the same way a few
wasps — six for the atom of carbon — flying around in Waterloo Station
will represent the extent to which the atom is crowded with electrons —
all the rest is emptiness. As we pass the whole structure of the universe
under review, from the giant nebulae and the vast interstellar and inter-
nebular spaces down to the tiny structure of the atom, little but vacant
space passes before our mental gaze. We live in a gossamer universe;
pattern, plan and design are there in abundance, but solid substance is
rare.

ATOMIC NUMBERS. The number of elecrons which fly round in orbits
in an atom is called the "atomic number" of the atom. Atoms of all
atomic numbers from i to 92 have been found, except for two missing
numbers 85 and 87. As already mentioned, it is highly probable that these
also exist, and that there are 92 "elements" whose atomic numbers occupy
the whole range of atomic numbers from i to 92 continuously.

The atom of atomic number unity is of course the simplest of all. It is
the hydrogen atom, in which a solitary electron revolves around a nucleus
whose charge of positive electricity is exactly equal in amount, although
opposite in sign, to the charge on the negative electron.

Next comes the helium atom of atomic number 2, in which two elec-
trons revolve about a nucleus which has four times the weight of the
hydrogen nucleus although carrying only twice its electric charge. After
this comes the lithium atom of atomic number 3, in which three electrons
revolve around a nucleus having six times the weight of the hydrogen
atom and three times its charge. And so it goes on, until we reach ura-
nium, the heaviest of all atoms known on earth, which has 92 electrons
describing orbits about a nucleus of 238 times the weight of the hydrogen
nucleus.

RADIO-ACTIVITY

While physical science was still engaged in breaking up the atom into
its component factors, it made the further discovery that the nuclei them-
selves were neither permanent nor indestructible. In 1896 Becquerel had
found that various substances containing uranium possessed the remark-
able property, as it then appeared, of spontaneously affecting photographic
plates in their vicinity. This observation led to the discoverv of a new

EXPLORING THE ATOM 183

property of matter, namely radio-activity. All the results obtained from
the study of radio-activity in the few following years were co-ordinated
in the hypothesis of "spontaneous disintegration" which Rutherford and
Soddy advanced in 1903. According to this hypothesis in its present form,
radio-activity indicates a spontaneous break-up of the nuclei of the atoms
of radio-active substances. These atoms are so far from being permanent
and indestructible that their very nuclei crumble away with the mere
lapse of time, so that what was once the nucleus of a uranium atom is
transformed, after sufficient time, into the nucleus of a lead atom.

The process of transformation is not instantaneous; it proceeds grad-
ually and by distinct stages. During its progress, three types of product are
emitted, which are designated a-rays, (3-rays, and y-rays.

These were originally described indiscriminately as rays because all
three were found to have the power of penetrating through a certain
thickness of air, metal, or other substance. It was not until later that their
true nature was discovered. It is well known that magnetic forces, such
as, for instance, occur in the space between the poles of a magnet, cause
a moving particle charged with electricity to deviate from a straight
course; the particle deviates in one direction or the other according as
it is charged with positive or negative electricity. On passing the various
rays emitted by radio-active substances through the space between the
poles of a powerful magnet, the a-rays were found to consist of particles
charged with positive electricity, and the P-rays to consist of particles
charged with negative electricity. But the most powerful magnetic forces
which could be employed failed to cause the slightest deviation in the
paths of the y-rays, from which it was concluded that either the y-rays
were not material particles at all, or that, if they were, they carried no
electric charges. The former of these alternatives was subsequently proved
to be the true one.

a-p ARTICLES. The positively charged particles which constitute a-rays
are generally described as a-particles. In 1909 Rutherford and Royds
allowed a-particles to penetrate through a thin glass wall of less than a
hundredth of a millimetre in thickness into a chamber from which they
could not escape — a sort of mouse-trap for a-particles. After the process
had continued for a long time, the final result was not an accumulation
of a-particles but an accumulation of the gas helium, the next simplest
gas after hydrogen. In this way it was established that the positively
charged a-particles are simply nuclei of helium atoms; the a-particles,
being positively charged, had attracted negatively charged electrons to
themselves out of the walls of the chamber and the result was a collection
of complete helium atoms.

184 MATTER, ENERGY, PHYSICAL LAW

The a-particles move with enormous speeds, which depend upon the
nature of the radio-active substance from which they have been shot out.
The fastest particles of all move with a speed of 12,800 miles a second;
even the slowest have a speed of 8800 miles a second, which is about
30,000 times the ordinary molecular velocity in air. Particles moving with
such speeds as these knock all ordinary molecules out of their way; this
explains the great penetrating power of the a-rays.

(3-p ARTICLES. By examining the extent to which their motion was
influenced by magnetic forces, the P-rays were found to consist of nega-
tively charged electrons, exactly similar to those which surround the
nucleus in all atoms. As an a-particle carries a positive charge equal in
amount to that of two electrons, an atom which has ejected an a-particle
is left with a deficiency of positive charge, or what comes to the same
thing, with a negative charge, equal to that of two electrons. Consequently
it is natural, and indeed almost inevitable, that the ejections of a-particles
should alternate with an ejection of negatively charged electrons, in the
proportion of one a-particle to two electrons, so that the balance of posi-
tive and negative electricity in the atom may be maintained. The (3-parti-
cles move with even greater speeds than the a-particles, many approaching
to within a few per cent, of the velocity of light (186,000 miles a
second). . . .

Y-RAYS. As has already been mentioned, the y-rays are not material
particles at all; they prove to be merely radiation of a very special kind.

Thus the break-up of a radio-active atom may be compared to the
discharge of a gun; the a-particle is the shot fired, the ^-particles are the
smoke, and the y-rays are the flash. The atom of lead which finally
remains is the unloaded gun, and the original radio-active atom, of
uranium or what not, was the loaded gun. And the special peculiarity of
radio-active guns is that they go of? spontaneously and of their own
accord. All attempts to pull the trigger have so far failed, or at least have
led to inconclusive results; we can only wait, and the gun will be found
to fire itself in time. . . .

In 1920, Rutherford, using radio-active atoms as guns, fired a-particles
at light atoms and found that direct hits broke up their nuclei. There is,
however, found to be a significant difference between the spontaneous
disintegration of the heavy radio-active atoms and the artificial disintegra-
tion of the light atoms; in the former case, apart from the ever-present
P-rays and y-rays, only a-particles are ejected, while in the latter case
a-particles were not ejected at all, but particles of only about a quarter
their weight, which proved to be identical with the nuclei of hydrogen
atoms. . . .

EXPLORING THE ATOM 185

ISOTOPES. Two atoms have the same chemical properties if the charges
of positive electricity carried by their nuclei are the same. The amount of
this charge fixes the number of electrons which can revolve around the
nucleus, this number being of course exactly that needed to neutralise
the electric field of the nucleus, and this in turn fixes the atomic number
of the element. And it has for long been known that the weights of all
atoms are, to a very close approximation, multiples of a single definite
weight. This unit weight is approximately equal to the weight of the
hydrogen atom, but is more nearly equal to a sixteenth of the weight
of the oxygen atom. The weight of any type of atom, measured in terms
of this unit, is called the "atomic weight" of the atom.

It used to be thought that a mass of any single chemical element, such
as mercury or xenon, consisted of entirely similar atoms, every one o£
which had not only the same atomic number but also the same atomic
weight. But Dr. Aston has shewn very convincingly that atoms of the
same chemical element, say neon or chlorine, may have nuclei of a great
many different weights. The various forms which the atoms of the same
chemical element can assume are known as isotopes being of course
distinguished by their different weights.

These weights are much nearer to whole numbers than were the old
"atomic" weights of the chemists. For instance the atomic weight of
chlorine used to be given as 35-5, and this was taken to mean that chlorine
consisted of a mixture of atoms each 35-5 times as massive as the hydrogen
atom. Aston finds that chlorine consists of a mixture of atoms of atomic
weights 35 and 37 (or more accurately 34-983 and 36-980), the former being
approximately three times as plentiful as the latter. In the same way a
mass of mercury, of which the mean atomic weight is about 200-6, is
found to be a mixture of seven kinds of atoms of atomic weights 196, 198,
199, 200, 201, 202, 204. Tin is a mixture of no fewer than eleven isotopes —
112, 114, 115, 116, 117, 118, 119, 120, 121, 122, 124.

PROTONS AND ELECTRONS. When the presence of isotopes is taken into
account, the atomic weights of all atoms prove to be far nearer to integral
numbers than had originally been thought. This, in conjunction with
Rutherford's artificial disintegration of atomic nuclei, led to the general
acceptance of the hypothesis that the whole universe is built up of only
two kinds of ultimate bricks, namely, electrons and protons. Each proton
carries a positive charge of electricity exactly equal in amount to the
negative charge carried by an electron, but has about 1847 times the weight
of the electron. Protons are supposed to be identical with the nucleus
of the hydrogen atom, all other nuclei being composite structures in which
both protons and electrons are closely packed together. For instance, the

186 MATTER, ENERGY, PHYSICAL LAW

nucleus of the helium atom, the a-particle, consists of four protons and
two electrons, these giving it approximately four times the weight of the
hydrogen atom, and a resultant charge equal to twice that of the nucleus
of the hydrogen atom.

NEUTRONS. Until quite recently this hypothesis was believed to give
a satisfactory and complete account of the structure of matter. Then in
1931 two German physicists, Bothe and Becker, bombarding the light
elements beryllium and boron with the very rapid a-particles emitted by
polonium, obtained a new and very penetrating radiation which they
were at first inclined to interpret as a kind of y-radiation. Subsequently
Dr. Chad wick of Cambridge shewed that it possessed properties which
were inconstant with this interpretation and made it clear that the radia-
tion consists of material objects of a type hitherto unknown to science.
To the greatest accuracy of which the experiments permit these objects
are found to have the same mass as the hydrogen atom, while their very
high penetrating power shews that if they have any electric charge at all,
it can only be a minute fraction at most of the charge of the electron.

Thus it seems likely that the radiation consists of uncharged particles
of the same mass as the proton — something quite new in a world which
until recently was believed to consist entirely of charged particles. Chad-
wick describes these new particles as "neutrons." Whether they are
themselves fundamental constituents of matter or not remains to be seen.
Chadwick has suggested that they may be composite structures, each
consisting of a proton and electron in such close combination that they
penetrate matter almost as freely as though they had no size at all. On the
other hand Heisenberg has considered the possibility that the neutron
may be fundamental, the nucleus of an atom being built up solely of
positively charged protons and uncharged neutrons, while the negative
electrons are confined to the regions outside the nucleus. On this view
there are just as many protons in the nucleus as there are electrons outside
the nucleus, the number of each being the atomic number of the element,
while the excess of mass needed to make up the atomic weight is provided
by the inclusion of the requisite number of neutrons in the nucleus.
Isotopes of the same element differ of course merely in having different
numbers of neutrons in their nuclei.

Rutherford and other physicists have considered the further possibility
that other kinds of neutrons, with double the mass of the hydrogen atom,
may also occur in atomic nuclei, a hypothesis for which there seems to
be considerable observational support.

POSITIVE ELECTRONS. Even more revolutionary discoveries were to
come. A few years ago it seemed a piece of extraordinary good luck that
in the a-particles nature herself had provided projectiles of sufficient

EXPLORING THE ATOM 187

shattering power to smash up the nucleus of the atom and disclose its
secrets to the observation of the physicist. More recently nature has been
found to provide yet more shattering projectiles in the cosmic radiation
which continually bombards the surface of the earth — probably from
outer space. This radiation has such a devastating effect on the atomic
nuclei that it is difficult to make much of the resulting collection of frag-
ments. It is, however, always possible to examine any debris, no matter
how involved, by noticing how the constituent particles move when acted
on by magnetic forces.

In 1932 C. D. Anderson made observations which suggested that this
debris contained, among other ingredients, particles having the same
positive charge as the proton, but a mass only comparable with, and pos-
sibly equal to, that of the electron. The existence of such particles has been
confirmed by Blackett and Occhialini at Cambridge. The new particles
may well be described as positively charged electrons, and so have been
named "positrons."

As these new particles are believed to emerge from atomic nuclei, it
would seem plausible to suppose that they must be normal constituents
of the nuclei. Yet the recent discovery of the neutron suggests other pos-
sibilities.

We have already mentioned the hypothesis, advocated by Heisenberg
and others, that the nucleus consists solely of neutrons and protons. Ander-
son has suggested that the proton may not be a fundamental unit in the
structure of matter, but may consist of a positron and a neutron in com-
bination. Every nucleus would then contain only neutrons and positrons,
and the positrons could be driven out by bombardment in the ordinary
way.

The objection to this view is that the debris of the nuclei shattered by
cosmic radiation is found to contain electrons as well as positrons, the
electrons emerging, so far as can be seen, from the same atomic nuclei as
the positrons. This has led Blackett and Occhialini to propound the
alternative hypothesis that the electrons and positrons are born in pairs as
the result of the processes of bombardment and disintegration of atomic
nuclei. At first this may seem a flagrant violation of all our views as to the
permanence of matter, but we shall see shortly that it is entirely in accord
with the present trend of physics.

It seems fairly certain that the positron has at most but a temporary
existence. For positrons do not appear to be associated with matter under
normal conditions, although they ought to abound if they were being
continually produced out of nuclei at anything like the rate which the
observations of Blackett and Occhialini seem to indicate. They might of

188 MATTER, ENERGY, PHYSICAL LAW

course rapidly disappear from view through entering into combination
with negatively charged particles to form some sort of permanent stable
structure, but it seems more probable, as Blackett and Occhialini them-
selves suggest, that they disappear from existence altogether by combining
with negative electrons. Just as a pair of electrons — one positively charged
and one negatively charged — can be born out of nothing but energy, so
they can die in one another's arms and leave nothing but energy behind.
We shall discuss the underlying physical mechanism almost immediately.
Before the existence of the positron had been observed, or even suspected
experimentally, Professor Dirac of Cambridge had propounded a mathe-
matical theory which predicted not only the existence of the positron, but
also the way in which it ought to behave. Dirac's theory is too abstrusely
mathematical to be explained here, but it predicts that a shower of posi-
trons ought gradually to fade away by spontaneous combination with
negative electrons, following the same law of decay as radio-active sub-
stances. And the average life of a positron is predicted to be one of only
a few millionths of a second, which amply explains why the positron can
live long enough to be photographed in a condensation chamber, but not
long enough to shew its presence elsewhere in the universe.

RADIATION

We have so far discussed only the material constituents of matter: we
have pictured the atom as being built up of some or all of the material
ingredients which we have described as electrons, protons, neutrons and
positrons. Yet this is not the whole story. If it were, every atom would
consist of a certain number of protons and neutrons with just sufficient
electrons and positrons to make the total electric charge equal to zero.
Thus, apart from the insignificant weights of electrons and positrons, the
weight of every atom would be an exact multiple of the weight of a
hydrogen atom. Experiment shews this not to be the case.

ELECTROMAGNETIC ENERGY. To get at the whole truth, we have to
recognise that, in addition to containing material electrons and protons>
with possible neutrons and positrons, the atom contains yet a further
ingredient which we may describe as electromagnetic energy. We may
think of this, although with something short of absolute scientific accuracy,
as bottled radiation.

If we disturb the surface of a pond with a stick, a series of ripples starts
from the stick and travels, in a series of ever-expanding circles, over the
surface of the pond. As the water resists the motion of the stick, we have
to work to keep the pond in a state of agitation. The energy of this work
is transformed, in part at least, into the energy of the ripples. We ca,n see

EXPLORING THE ATOM 189

that the ripples carry energy about with them, because they cause a floating
cork or a toy boat to rise up against the earth's gravitational pull. Thus
the ripples provide a mechanism for distributing over the surface of the
pond the energy that we put into the pond through the medium of the
moving stick.

Light and all other forms of radiation are analogous to water ripples or
waves, in that they distribute energy from a central source. The sun's
radiation distributes through space the vast amount of energy which is
generated inside the sun. We hardly know whether there is any actual
wave motion in light or not, but we know that both light and all other
types of radiation are propagated in such a form that they have many of
the properties of a succession of waves.

The different colours of light which in combination constitute sunlight
can be separated out by passing the light through a prism, thus forming
a rainbow or "spectrum" of colors. The separation can also be effected by
an alternative instrument, the diffraction grating, which consists merely
of a metal mirror with a large number of parallel lines scratched evenly
across its surface. The theory of the action of this latter instrument is
well understood; it shews that actually the light is separated into waves
of different wave-lengths. (The wave-length in a system of ripples is the
distance from the crest of one ripple to that of the next, and the term may
be applied to all phenomena of an undulatory nature.) This proves that
different colours of light are produced by waves of different lengths, and
at the same time enables us to measure the lengths of the waves which
correspond to the different colours of light.

These prove to be very minute. The reddest light we can see, which is

•2

that of longest wave-length, has a wave-length of only — inch

100,000

(7.5 Xio"5 cm.); the most violet light we can see has a wave-length only
half of this, or 0-000015 inch. Light of all colours travels with the same
uniform speed of 186,000 miles, or 3Xio10 centimetres, a second. The
number of waves of red light which pass any fixed point in a second is
accordingly no fewer than four hundred million million. This is called
the "frequency" of the light. Violet light has the still higher frequency
of eight hundred million million; when we see violet light, eight hundred
million million waves of light enter our eyes each second.

The spectrum of analysed sunlight appears to the eye to stretch from
red light at one end to violet light at the other, but these are not its true
limits. When certain chemical salts are placed beyond the violet end of
the visible spectrum, they are found to shine vividly, shewing that even
out here energy is being transported, although in invisible form. And

190 MATTER, ENERGY, PHYSICAL LAW

other methods make it clear that the same is true out beyond the red end
of the spectrum. A thermometer, or other heat-measuring instrument,
placed here will shew that energy is being received here in the form of
heat.

In this way we find that regions of invisible radiation stretch indefi-
nitely from both ends of the visible spectrum. From one end — the red —
we can pass continuously to waves of the type used for wireless transmis-
sion, which have wave-lengths of the order of hundreds, or even thousands,
of yards. From the violet end, we pass through waves of shorter and ever
shorter wave-length — all the various forms of ultra-violet radiation. At
wave-lengths of from about a hundredth to a thousandth of the wave-
length of visible light, we come to the familiar X-rays, which penetrate
through inches of our flesh, so that we can photograph the bones inside.
Far out even beyond these, we come to the type of radiation which con-
stitutes the Y-rays, its wave-length being of the order of

10,000,000,000

inch, or only about a hundred-thousandth part of the wave-length of
visible light. Thus the y-rays may be regarded as invisible radiation of
extremely short wave-length. We shall discuss the exact function they
serve later. For the moment let us merely remark that in the first instance
they served the extremely useful function of fogging BecquereFs photo-
graphic plates, thus leading to the detection of the radio-active property
of matter.

It is a commonplace of modern electromagnetic theory that energy of
every kind carries weight about with it, weight which is in every sense as
real as the weight of a ton of coal. A ray of light causes an impact on any
surface on which it falls, just as a jet of water does, or a blast of wind, or
the fall of a ton of coal; with a sufficiently strong light one could knock a
man down just as surely as with the jet of water from a fire hose. This is
not a mere theoretical speculation. The pressure of light on a surface has
been both detected and measured by direct experiment. The experiments
are extraordinarily difficult because, judged by all ordinary standards, the
weight carried by radiation is exceedingly small; all the radiation emitted
from a 50 horse-power searchlight working continuously for a century
weighs only about a twentieth of an ounce.

It follows that any substance which is emitting radiation must at the
same time be losing weight. In particular, the disintegration of any radio-
active substance must involve a decrease of weight, since it is accompanied
by the emission of radiation in the form of Y-rays. The ultimate fate of an
ounce of uranium may be expressed by the equation:

EXPLORING THE ATOM 191

f 0-8653 °unce lead,

i ounce uranium =«| 0-1345 " helium,
[0-0002 " radiation.

The lead and helium together contain just as many electrons and just
as many protons as did the original ounce of uranium, but their combined
weight is short of the weight of the original uranium by about one part
in 4000. Where 4000 ounces of matter originally existed, only 3999 now
remain; the missing ounce has gone off in the form of radiation.

This makes it clear that we must not expect the weights of the various
atoms to be exact multiples of the weight of the hydrogen atom; any
such expectation would ignore the weight of the bottled-up electro-mag-
netic energy which is capable of being set free and going off into space in
the form of radiation as the atom changes its make-up. The weight of this
energy is relatively small, so that the weights of the atoms must be ex-
pected to be approximately, although not exactly, integral multiples of
that of the hydrogen atom, and this expectation is confirmed. The exact
weight of our atomic building is not simply the total weight of all its
bricks; something must be added for the weight of the mortar— the electro-
magnetic energy — which keeps the bricks bound together.

Thus the normal atom consists of its material constituents — protons,
electrons, neutrons and positrons, or some at least of these — and also of
energy, which also contributes something to its weight. When the atom
re-arranges itself, either spontaneously or under bombardment, protons
and electrons, or other fragments of its material structure, may be shot off
in the form of a- and (3-particles, and energy may also be set free in the
form of radiation. This radiation may either take the form of y-rays, or
of other forms of visible and invisible radiation. The final weight of the
atom will be obtained by deducting from its original weight not only
the weight of all the ejected electrons and protons, but also the weight
of all the energy which has been set free as radiation.

QUANTUM THEORY

The series of concepts which we now approach are difficult to grasp
and still more difficult to explain, largely, no doubt, because our minds
receive no assistance from our everyday experience of nature. It becomes
necessary to speak mainly in terms of analogies, parables and models which
can make no claim to represent ultimate reality; indeed, it is rash to
hazard a guess even as to the direction in which ultimate reality lies.

The laws of electricity which were in vogue up to about the end of the
nineteenth century— the famous laws of Maxwell and Faraday— required

192 MATTER, ENERGY, PHYSICAL LAW

that the energy of an atom should continually decrease, through the atom
scattering energy abroad in the form of radiation, and so having less and
less left for itself. These same laws predicted that all energy set free in
space should rapidly transform itself into radiation of almost infinitesimal
wave-length. Yet these things simply did not happen, making it obvious
that the then prevailing electrodynamical laws had to be given up.

CAVITY-RADIATION. A crucial case of failure was provided by what is
known as "cavity-radiation." A body with a cavity in its interior is heated
up to incandescence; no notice is taken of the light and heat emitted by
its outer surface, but the light imprisoned in the internal cavity is let out
through a small window and analysed into its constituent colours by a
spectroscope or diffraction grating. This is the radiation that is known
as "cavity-radiation." It represents the most complete form of radiation
possible, radiation from which no colour is missing, and in which every
colour figures at its full strength. No known substance ever emits quite
such complete radiation from its surface, although many approximate to
doing so. We speak of such bodies as "full radiators."

The nineteenth-century laws of electromagnetism predicted that the
whole of the radiation emitted by a full radiator or from a cavity ought
to be found at or beyond the extreme violet end of the spectrum, inde-
pendently of the precise temperature to which the body had been heated.
In actual fact the radiation is usually found piled up at exactly the op-
posite end of the spectrum, and in no case does it ever conform to the
predictions of the nineteenth century laws, or even begin to think of
doing so.

In the year 1900 Professor Planck of Berlin discovered experimentally
the law by which cavity-radiation is distributed among the different
colours of the spectrum. He further shewed how his newly-discovered law
could be deduced theoretically from a system of electromagnetic laws
which differed very sensationally from those then in vogue.

Planck imagined all kinds of radiation to be emitted by systems of
vibrators which emitted light when excited, much as tuning forks emit
sound when they are struck. The old electrodynamical laws predicted
that each vibration should gradually come to rest and then stop, as the
vibrations of a tuning fork do, until the vibrator was in some way excited
again. Rejecting all this, Planck supposed that a vibrator could change
its energy by sudden jerks, and in no other way; it might have one, two,
three, four or any other integral number of units of energy, but no inter-
mediate fractional numbers, so that gradual changes of energy were
rendered impossible. The vibrator, so to speak, kept no small change,
and could only pay out its energy a shilling at a time until it had none

EXPLORING THE ATOM 193

left. Not only so, but it refused to receive small change, although it was
prepared to accept complete shillings. This concept, sensational, revolu-
tionary and even ridiculous, as many thought it at the time, was found to
lead exactly to the distribution of colours actually observed in cavity-ra-
diation.

In 1917 Einstein put the concept into the more precise form which now
prevails. According to a theory previously advanced by Professor Niels
Bohr of Copenhagen, an atomic or molecular structure does not change
its configuration, or dissipate away its energy, by gradual stages; on the
contrary, the changes are so abrupt that it is almost permissible to regard
them as a series of sudden jumps or jerks. Bohr supposed that an atomic
structure has a number of possible states or configurations which are
entirely distinct and detached one from another, just as a weight placed
on a staircase has only a possible number of positions; it may be 3 stairs
up, or 4 or 5, but cannot be 3 % or 3% stairs up. The change from one
position to another is generally effected through the medium of radiation.
The system can be pushed upstairs by absorbing energy from radiation
which falls on it, or may move downstairs to a state of lower energy and
emit energy in the form of radiation in so doing. Only radiation of a
certain definite colour, and so of a certain precise wave-length, is of any
account for effecting a particular change of state. The problem of shifting
an atomic system is like that of extracting a box of matches from a penny-
in-the-slot machine; it can only be done by a special implement, to wit a
penny, which must be of precisely the right size and weight — a coin which
is either too small or too large, too light or too heavy, is doomed to fail.
If we pour radiation of the wrong wave length on to an atom, we may re-
produce the comedy of the millionaire whose total wealth will not procure
him a box of matches because he has not a loose penny, or we may re*
produce the tragedy of the child who cannot obtain a slab of chocolate
because its hoarded wealth consists of farthings and half-pence, but we
shall not disturb the atom. When mixed radiation is poured on to a col-
lection of atoms, these absorb the radiation of just those wave-lengths
which are needed to change their internal states, and none other; radiation
of all other wave-lengths passes by unaffected.

This selective action of the atom on radiation is put in evidence in a
variety of ways; it is perhaps most simply shewn in the spectra of the sun
and stars. Dark lines similar to those which Fraunhofer observed in the
solar spectrum are observed in the spectra of practically all stars and we
can now understand why this must be. Light of every possible wave-length
streams out from the hot interior of a star, and bombards the atoms which
form its atmosphere. Each atom drinks up that radiation which is of

194 MATTER, ENERGY, PHYSICAL LAW

precisely the right wave-length for it, but has no interaction of any kind
with the rest, so that the radiation which is finally emitted from the star
is deficient in just the particular wave-lengths which suit the atoms. Thus
the star shews an absorption spectrum of fine lines. The positions of these
lines in the spectrum shew what types of radiation the stellar atoms have
swallowed, and so enable us to identify the atoms from our laboratory
knowledge of the tastes of different kinds of atoms for radiation. But
what ultimately decides which types of radiation an atom will swallow,
and which it will reject?

It had been part of Planck's theory that radiation of each wave-length
has associated with it a certain amount of energy, called the "quantum,"
which depends on the wave-length and on nothing else. The quantum
is supposed to be proportional to the "frequency," or number of vibrations
of the radiation per second, and so is inversely proportional to the wave-
length of the radiation — the shorter the wave-length, the greater the
energy of the quantum, and conversely. Red light has feeble quanta, violet
light has energetic quanta, and so on.

Einstein now supposed that radiation of a given type could effect an
atomic or molecular change, only if the energy needed for the change
is precisely equal to that of a single quantum of the radiation. This is
commonly known as Einstein's law; it determines the precise type of
radiation needed to work any atomic or molecular penny-in-the-slot
mechanism.

We notice that work which demands one powerful quantum cannot
be performed by two, or indeed by any number whatever, of feeble quanta.
A small amount of violet (high-frequency) light can accomplish what no
amount of red (low-frequency) light can effect.

The law prohibits the killing of two birds with one stone, as well as
the killing of one bird with two stones; the whole quantum is used up in
effecting the change, so that no energy from this particular quantum is
left over to contribute to any further change. This aspect of the matter is
illustrated by Einstein's photochemical law: "in any chemical reaction
which is produced by the incidence of light, the number of molecules
which are affected is equal to the number of quanta of light which are
absorbed." Those who manage penny-in-the-slot machines are familiar
with a similar law: "the number of articles sold is exactly equal to the
number of coins in the machine."

If we think of energy in terms of its capacity for doing damage, we see
that radiation of short wave-length can work more destruction in atomic
structures than radiation of long wave-length—a circumstance with
which every photographer is painfully familiar; we can admit as much

EXPLORING THE ATOM 195

red light as we please without any damage being done, but even the
tiniest gleam of violet light spoils our plates. Radiation of sufficiently
short wave-length may not only rearrange molecules or atoms; it may
break up any atom oa which it happens to fall, by shooting out one of
its electrons, giving rise to what is known as photoelectric action. Again
there is a definite limit of frequency, such that light whose frequency
is below this limit does not produce any effect at all, no matter how in-
tense it may be; whereas as soon as we pass to frequencies above this
limit, light of even the feeblest intensity starts photoelectric action at
once. Again the absorption of one quantum breaks up only one atom,
and further ejects only one electron from the atom. If the radiation has
a frequency above this limit, so that its quantum has more energy than
the minimum necessary to remove a single electron from the atom, the
whole quantum is still absorbed, the excess energy now being used in
endowing the ejected electron with motion.

ELECTRON ORBITS. These concepts are based upon Bohr's supposition
that only a limited number of orbits are open to the electrons in an atom,
all others being prohibited for reasons which Bohr's theory did not fully
explain, and that an electron is free to move from one permitted orbit
to another under the stimulus of radiation. Bohr himself investigated the
way in which the various permitted orbits are arranged. Modern investi-
gations indicate the need for a good deal of revision of his simple concepts,
but we shall discuss these in some detail, partly because Bohr's picture of
the atom still provides the best working mechanical model we have, and
partly because an understanding of his simple theory is absolutely es-
sential to the understanding of the far more intricate theories which are
beginning to replace it.

The hydrogen atom, as we have already seen, consists of a single proton
as central nucleus, with a single electron revolving around it. The nucleus,
with about 1847 times the weight of the electron, stands practically at
rest unagitated by the motion of the latter, just as the sun remains practi-
cally undisturbed by the motion of the earth round it. The nucleus and
electron carry charges of positive and negative electricity, and therefore
attract one another; this is why the electron describes an orbit instead of
flying of? in a straight line, again like the earth and sun. Furthermore,
the attraction between electric charges of opposite sign, positive and
negative, follows, as it happens, precisely the same law as gravitation,
the attraction falling off as the inverse square of the distance between the
two charges. Thus the nucleus-electron system is similar in all respects
to a sun-planet system, and the orbits which an electron can describe
around a central nucleus are precisely identical with those which a planet

196 MATTER, ENERGY, PHYSICAL LAW

can describe about a central sun; they consist of a system of ellipses each
having the nucleus in one focus.

Yet the general concepts of quantum-dynamics prohibit the electron
from moving in all these orbits indiscriminately. Bohr's original theory
supposed that the electron in the hydrogen atom could move only in
certain circular orbits whose diameters were proportional to the squares
of the natural numbers, and so to i, 4, 9, 16, 25, .... Bohr subsequently
modified this very simple hypothesis, and the theory of wave-mechanics
has recently modified it much further.

Yet it still remains true that the hydrogen atom has always very approxi-
mately the same energy as it would have if the electron were describing
one or another of these simple orbits of Bohr. Thus, when its energy
changes, it changes as though the electron jumped over from one to another
of these orbits. For this reason it is easy to calculate what changes of
energy a hydrogen atom can experience — they are precisely those which
correspond to the passage from one Bohr orbit to another. For example,
the two orbits of smallest diameters in the hydrogen atom differ in energy
by i6Xio~12 erg. If we pour radiation of the appropriate wave-length on
to an atom in which the electron is describing the smallest orbit of all, it
crosses over to the next orbit, absorbing i6Xio"12 erg of energy in the
process, and so becoming temporarily a reservoir of energy holding 16
X io"12 erg. If the atom is in any way disturbed from outside, it may of
course discharge the energy at any time, or it may absorb still more
energy and so increase its store.

If we know all the orbits which are possible for an atom of any type, it
is easy to calculate the changes of energy involved in the various transi-
tions between them. As each transition absorbs or releases exactly one
quantum of energy, we can immediately deduce the frequencies of the
light emitted or absorbed in these transitions. In brief, given the arrange-
ment of atomic orbits, we can calculate the spectrum of the atom. In
practice the problem of course takes the converse form: given the spec-
trum, to find the structure of the atom which emits it. Bohr's model of
the hydrogen atom is a good model at least to this extent — that the spec-
trum it would emit reproduces the hydrogen spectrum almost exactly.
Yet the agreement is not quite perfect, and for this reason it is now
generally accepted that Bohr's scheme of orbits is inadequate to account
for actual spectra. We continue to discuss Bohr's scheme, not because the
atom is actually built that way, but because it provides a working model
which is good enough for our present purpose.

An essential, although at first sight somewhat unexpected, feature of
the whole theory is that even if the hydrogen atom charged with its

EXPLORING THE ATOM 197

16 X io"12 erg of energy is left entirely undisturbed, the electron must,
after a certain time, lapse back spontaneously to its original smaller orbit,
ejecting its 16 X io"12 erg of energy in the form of radiation in so doing.
Einstein shewed that, if this were not so, then Planck's well-established
"cavity-radiation" law could not be true. Thus, a collection of hydrogen
atoms in which the electrons describe orbits larger than the smallest pos-
sible orbit is similar to a collection of uranium or other radio-active atoms,
in that the atoms spontaneously fall back to their states of lower energy
as the result merely of the passage of time.

The electron orbits in more complicated atoms have much the same
general arrangement as in the hydrogen atom, but are different in size.
In the hydrogen atom the electron normally falls, after sufficient time, to
the orbit of lowest energy and stays there. It might be thought by analogy
that in more complicated atoms in which several electrons are describing
orbits, all the electrons would in time fall into the orbit of lowest energy
and stay there. Such does not prove to be the case. There is never room
for more than one electron in the same orbit. This is a special aspect of
a general principle which appears to dominate the whole of physics. It
has a name — "the exclusion-principle" — but this is about all as yet; we have
hardly begun to understand it. In another of its special aspects it becomes
identical with the old familiar cornerstone of science which asserts that
two different pieces of matter cannot occupy the same space at the same
time. Without understanding the underlying principle, we can accept
the fact that two electrons not only cannot occupy the same space, but
cannot even occupy the same orbit. It is as though in some way the electron
spread itself out so as to occupy the whole of its orbit, thus leaving
room for no other. No doubt this must not be accepted as a literal
picture of things, and yet the modern theory of wave-mechanics sug-
gests that in some sense (which we cannot yet specify with much pre-
cision) the orbits of lowest energy in the hydrogen atom are possible orbits
just because the electron can completely fill them, and that adjacent orbits
are impossible because the electron would fill them t or ii times over,
and similarly for more complicated atoms. In this connection it is per-
haps significant that no single known phenomenon of physics makes it
possible to say that at a given instant an electron is at such or such a
point in an orbit of lowest energy; such a statement appears to be quite
meaningless and the condition of an atom is apparently specified with
all possible precision by saying that at a given instant an electron is in
such an orbit, as it would be, for instance, if the electron had spread
itself out into a ring. We cannot say the same of other orbits. As we pass
to orbits of higher energy, and so of greater diameter, the indeterminate-

198 MATTER, ENERGY, PHYSICAL LAW

ness gradually assumes a different form, and finally becomes of but little
importance. Whatever form the electron may assume while it is describ-
ing a little orbit near the nucleus, by the time it is describing a very
big orbit far out it has become a plain material particle charged with
electricity.

Thus, whatever the reason may be, electrons which are describing orbits
in the same atom must all be in different orbits. The electrons in their
orbits are like men on a ladder; just as no two men can stand on the
same rung, so no two electrons can ever follow one another round in the
same orbit. The neon atom, for instance, with 10 electrons is in its normal
state of lowest energy when its 10 electrons each occupy one of the 10
orbits whose energy is lowest. For reasons which the quantum theory has
at last succeeded in elucidating, there are, in every atom, two orbits in
which the energy is equal and lower than in any other orbit. After this
come eight orbits of equal but substantially higher energy, then 18 orbits
of equal but still higher energy, and so on. As the electrons in each
of these various groups of orbits all have equal energy, they are commonly
spoken of, in a graphic but misleading phraseology, as rings of electrons.
They are designated the K-ring, the L-ring, the M-ring and so on.
The ,K-ring, which is nearest to the nucleus, has room for two electrons
only. Any further electrons are pushed out into the L-ring, which has room
for eight electrons, all describing orbits which are different but of equal
energy. If still more electrons remain to be accommodated, they must
go into the M-ring and so on.

In its normal state, the hydrogen atom has one electron in its K~ring,
while the helium has two, the L, M, and higher rings being unoccupied.
The atom of next higher complexity, the lithium atom, has three electrons,
and as only two can be accommodated in its X-ring, one has to wander
round in the outer spaces of the L-ring. In beryllium with four electrons,
two are driven out into the L-ring. And so it goes on, until we reach
neon with 10 electrons, by which time the L-ring as well as the inner X-
ring is full up. In the next atom, sodium, one of the n electrons is
driven out into the still more remote M-ring, and so on. Provided the
electrons are not being excited by radiation or other stimulus, each atom
sinks in time to a state in which its electrons are occupying its orbits of
lowest energy, one in each.

So far as our experience goes, an atom, as soon as it reaches this
state, becomes a true perpetual motion machine, the electrons continuing
to move in their orbits (at any rate on Bohr's theory) without any of
the energy of their motion being dissipated away, either in the form of
radiation or otherwise. It seems astonishing and quire incomprehensible

EXPLORING THE ATOM 199

that an atom in such a state should not be able to yield up its energy
still further, but, so far as our experience goes, it cannot. And this
property, little though we understand it, is, in the last resort, responsible
for keeping the universe in being. If no restriction of this kind inter-
vened, the whole material energy of the universe would disappear in
the form of radiation in a few thousand-millionth parts of a second. If the
normal hydrogen atom were capable of emitting radiation in the way
demanded by the nineteenth-century laws of physics, it would, as a direct
consequence of this emission of radiation, begin to shrink at the rate of
over a metre a second, the electron continually falling to orbits of lower
and lower energy. After about a thousand-millionth part of a second the
nucleus and the electron would run into one another, and the whole atom
would probably disappear in a flash of radiation. By prohibiting any
emission of radiation except by complete quanta, and by prohibiting any
emission at all when there are no quanta available for dissipation, the
quantum theory succeeds in keeping the universe in existence as a going
concern.

It is difficult to form even the remotest conception of the realities under-
lying all these phenomena. The recent branch of physics known as
"wave mechanics" is at present groping after an understanding, but so
far progress has been in the direction of co-ordinating observed phenomena
rather than in getting down to realities. Indeed, it may be doubted
whether we shall ever properly understand the realities ultimately in-
volved; they may well be so fundamental as to be beyond the grasp of the
human mind.

It is just for this reason that modern theoretical physics is so difficult
to explain, and so difficult to understand. It is easy to explain the motion
of the earth round the sun in the solar system. We see the sun in the
sky; we feel the earth under our feet, and the concept of motion is
familiar to us from everyday experience. How different when we try
to explain the analogous motion of the electron round the proton in
the hydrogen atom! Neither you nor I have any direct experience of
either electrons or protons, and no one has so far any inkling of what
they are really like. So we agree to make a sort of model in which the
electron and proton are represented by the simplest things known to us,
tiny hard spheres. The model works well for a time and then suddenly
breaks in our hands. In the new light of the wave mechanics, the hard
sphere is seen to be hopelessly inadequate to represent the electron. A hard
sphere has always a definite position in space; the electron apparently
has not. A hard sphere takes up a very definite amount of room, an
electron— well, it is probably as meaningless to discuss how much room an

200 MATTER, ENERGY, PHYSICAL LAW

electron takes up as it is to discuss how much room a fear, an anxiety or
an uncertainty takes up, but if we are pressed to say how much room
an electron takes up, perhaps the best answer is that it takes up the whole
of space. A hard sphere moves from one point to the next; our model
electron, jumping from orbit to orbit in Bohr's model hydrogen atom,
certainly does not behave like any hard sphere of our waking experience,
and the real electron — if there is any such thing as a real electron —
probably even less. Yet as our minds have so far failed to conceive any
better picture of the atom than this very imperfect model, we can only
proceed by describing phenomena in terms of it.

Edition of 1934

Touring the Atomic World

LAWRENCE'S CYCLOTRON
HENRY SCHACHT

SOME TIME WHEN YOU HAVEN'T ANYTHING ELSE TO
do at the moment why not go on a trip into an invisible world ? No
money is required, no packing, or long, tiresome rides. Just a fertile imag-
ination. Pick up an object, any object, and look at it. Then imagine that
you are slowly shrinking in size. Say the object you are holding is a white
handkerchief. As you shrink, the handkerchief seems to expand enor-
mously. At first it looks as big as a circus tent. But you're still becoming
smaller. Now as you stand on the handkerchief, it forms a great, white
plain as far as your eye can see. Still you grow smaller, and you become
aware that great cracks are opening in your white plain. These aren't the
result of an earthquake, nor the crevasses in a glacier. They simply prove
that no matter how tightly woven your handkerchief may seem to be there
are spaces between the threads. As you grow smaller still, the spaces seem
to widen and the threads, themselves, become larger. You can sit on one
now and hang your feet over the side.

TOURING THE ATOMIC WORLD 201

The thread seems to be a very safe place. Soon you can wander around
on top of it, looking over the side and enjoying your trip to the utmost.
But there are still surprises to come. As yet you aren't even within sight
of the invisible world you have started out to visit. Still, you're getting
there. For now the ground — or rather the thread — is beginning to open up
beneath your feet. You see, you're still diminishing in size. In comparison,
the thread is still becoming larger. Now you're beginning to find from
first hand experience that threads are made up of fibers. And there are
spaces between the fibers, just as there are between the threads. So you
pick your way carefully along first one fiber and then another, being care-
ful not to fall into the canyons between them. This seems easy until you
find that the fibers themselves are beginning to show gaps. The one that
at first was just a platform on which you stood is now assuming giant
proportions, stretching away in all directions. You seem to be getting so
small that you can just sink right through it. And that's exactly what is
happening, for you slip through the surface of the fiber, disappear into it.
And the next thing you know you're falling through space, like someone
pitched out of a Buck Rogers spaceship.

As you fall, you see all about you planets and suns and moons. They are
arranged into tight little solar systems. And then, if you know your atomic
physics, you'll realize that you have arrived in the hitherto invisible world
of the atoms. You are falling through an ultramicroscopic universe, peo-
pled by solar systems so infinitesimal that billions of them are contained
in the fiber you have just slipped through. Yet there is still room for your
much shrunken body to pass without even grazing them. Now you can
pick out those sections of the atom that you were told about in school.
You can see the bodies that look like planets and moons rotating around a
central sun. You know that those are the electrons, electrical particles hav-
ing a negative electrical charge. Then you turn your attention to the cen-
tral sun, itself. You know that this is the nucleus of the atom, the impor-
tant central mass that determines the character of the entire atomic solar
system. It is made up of a number of different particles, known variously
as protons, mesotrons, and neutrons. You can see all these things. But,
unfortunately, that is as far as you can go. You cannot explore them
freely as you have explored the handkerchief. For such a journey you need
a special passport available to only a few men on earth. Even they have
not yet developed the last passport of all, the one that will allow them to
solve all the mysteries of the nucleus of the atom.

The man who has come closest to making the entire trip through the
invisible atomic world is Dr. Ernest O. Lawrence, developer of the world
famous cyclotron on the University of California campus and winner of

202 MATTER, ENERGY, PHYSICAL LAW

that most coveted award, the Nobel Prize in Physics for 1939. Shake off
your imaginative spell, come back to your normal size, and let's go over
the story of Dr. Lawrence's trips into the atomic unknown. After your
journey you have the proper perspective to appreciate the difficulties he
and his colleagues have overcome and those they hope to overcome in the
near future. You know now from your own experience that nothing we
can see in this world of ours is solid no matter how it feels to the touch.
Everything we use, everything that we see, feel, touch, or taste is made
in the final analysis, not of those things that we call paper, or sugar, or salt,
or wood, but of tiny solar systems, called atoms, ultramicroscopic worlds
which no one yet has ever completely explored, but which hold the secret
to a possible re-making of our world in the forms which we desire. So,
having familiarized yourself with the invisible world through your imag-
inative journey, take another mind's eye tour with the writer, this time
to the University of California campus where in the Radiation Laboratory
we pick up the story of one of science's most valuable and remarkable
developments, the cyclotron.

This machine, now copied in all parts of the world, was first set in oper-
ation at the University in 1929. It was the answer to a physicist's dream
and proof of the old saw that necessity is the mother of invention. Physi-
cists had been interested in atoms for many years. They knew about their
arrangement with the electrons whirling in orbits about the central
nucleus. They also knew that the proportion of negative and positive
charges in the nucleus and the number of these charges present (in other
words, the pattern and size of the nucleus) determined whether the atom
was one of hydrogen gas, carbon, gold, iron, molybdenum, or some other
element. However, this knowledge was not enough. What the physicists
wanted to do was to tear the atomic world apart and see what made it tick.
This, as they knew, was by no means an easy task.

The atom is like a case-hardened steel safe without lock or combination.
You can break into it only by main force and its resistance is powerful.
Around itself it sets up a field of force which presents a stout barricade
against invasion. The nucleus is tightly held together by the mutual elec-
trical attraction of the particles from which it is formed. This sets up a
second barrier. And, finally, the atom's lack of size works to the disadvan-
tage of anyone attempting to explore its mysteries. After your imagina-
tive journey through the handkerchief, you probably won't be surprised
to find that atoms are so small it would take the entire population of the
earth ten thousand years to count the number of them in a drop of water.
Even then each individual counter would have to be reduced to one-bil-
lionth of an inch in height in order to see an atom. At that he would be

TOURING THE ATOMIC WORLD 203

several cuts larger than you were when you fell through the fiber into the
atomic universe. So you see the atom's lack of size presents a real prob-
lem. The use of any ordinary weapon in an assault on the nucleus would
be like using a sledge hammer to break into a grain of dust. What is
required is some force small enough to enter the atom and still powerful
enough to break down the electrical barricades surrounding it.

Lord Rutherford, the famous English physicist, found such a force in
the natural rays emitted by radium. These are called "alpha rays" by the
scientists and are composed of steady streams of helium atoms thrown out
at a pace of approximately 10,000 miles per second. They are caused by the
disintegration of the radium. In 1919 Lord Rutherford used these rays to
perform the first known transmutation of elements; or the act of changing
one element into another. The ancient alchemists tried to perform trans-
mutation by heating base metals with what they called "philosopher's
stone" to produce gold. Much to their dismay gold was never produced.
Lord Rutherford went about his transmutation operations in quite a dif-
ferent way. He sent "alpha rays" crashing into the nuclei of nitrogen gas
atoms and, after the shooting was over, out came oxygen. This may seem
complicated but it was really very simple. All that happened was that the
"alpha rays" crashing into the nitrogen atoms knocked a few particles out
of their nuclei. The nature of any element is dependent upon the size and
pattern of its nucleus, and the nuclei of the nitrogen atoms were so rear-
ranged that a new element, oxygen, was formed.

The success of Lord Rutherford's experiments set physicists all over the
world at bombarding atoms with the rays of radium. Soon they found
that when atomic nuclei were rearranged under the impact of a flying
particle, tremendous amounts of energy were released. This energy, it
appeared, was locked up inside the atom, and, when a few particles were
split off the nucleus, some of the power leaked out. A little of it would go
a long, long way. For the sub-atomic energy, as the power is called, locked
up in the nuclei of the atoms in a fraction of a pint of water would drive
a battleship from New York to Liverpool and back again. Physicists were
greatly intrigued by the knowledge that some of this energy could be
released by bombarding and partially breaking up the nuclei of atoms. It
revived the hope that some day atomic energy of which there is a great
and unfailing source might be used, instead of steam or electricity, to turn
the wheels of the world's factories.

Yet for all their speculation as to what these discoveries might mean
the physicists still knew that radium was not the ideal atom-blaster they
sought. They were really in the same position as the medical men before
the invention of the microscope, and the astronomers before the invention

204 MATTER, ENERGY, PHYSICAL LAW

of the telescope. These two inventions revolutionized medicine and
astronomy. The physicists stood on the threshold of discoveries that would
revolutionize our knowledge of the structure of the world and everything
that lives on it. They needed another passport into the unknown. Radium
had provided them with entry into the problem. But radium was too
expensive for one thing and also it was not a very copious source of "alpha
rays." A search began for some other method of smashing atoms, and thus
the stage was set for Dr. E. O. Lawrence and his now-famous cyclotron.

Lawrence, who was only beginning his University career at that time,
had abandoned the idea of searching for some 'force strong enough nat-
urally to break into the atomic citadel. Instead he proposed to take some
weaker force and step it up by degrees until finally when unleashed, it
could overpower the atom's defense. Or at least storm a -section of the
barricade. To test his theory he built the first cyclotron, an almost pocket-
sized model. It worked, as did a series of other slightly larger ones. So Dr.
Lawrence began laying his plans for a machine that could really generate
some power. The old Federal Telegraph Company had been forced in
1918 to abandon its plans for constructing a wireless station in China. As
a result, Federal still had a 6o-ton magnet on* its hands. Dr. Leonard F.
Fuller, then vice-president of Federal and in his' first year as -chairman of
the department of electrical engineering at the University, persuaded the
board of directors to give the magnet to Dr. Lawrence. Around it the
young physicist built an 85-ton cyclotron, the first really efficient atom-
smasher the world was to know.

Of course, Dr. Lawrence and his co-workers at the Radiation Labora-
tory had no inkling that they were about to turn the physical world topsy-
turvy. They just hoped the monster would work as well in fact as it did
on paper.

On paper it was all very simple. First, a circular chamber was placed
between the poles of the magnet. Then all air was removed from the
chamber and heavy hydrogen gas allowed to- flow in. This so-called heavy
hydrogen behaves in the same way as ordinary hydrogen. However, while
the nuclei of ordinary hydrogen atoms contain one positively charged par-
ticle, or proton, heavy hydrogen nuclei contain two such particles plus
one electron. Consequently, they weigh just twice as much as the nuclei
of ordinary hydrogen atoms. They are known as deuterons.

The deuteron's added weight makes it an ideal atomic bullet. And here
is how Dr. Lawrence planned to send streams of deuterons crashing into
the nuclei of other atoms in a constant, destructive barrage: Inside the
cyclotron chamber was a heated filament that emitted streams of elec-
trons. These particles would collide with the electrons surrounding the

TOURING THE ATOMIC WORLD 205

nuclei of the hydrogen atoms and in the ensuing mixup the nuclei and
their satellites would become separated. The deuterons would be left free
to float around the chamber. Eventually, the magnetic force set up by the
cyclotron's magnet would pull them between two metal grids separated
by a space across which an alternating electrical current of ten or fifteen
thousand volts would be operating. As the deuterons floated into this
space, they would receive a heavy shock, and under this stimulus fly off
to'ward the side of the chamber. But the magnetic field would pull them
back again in a semi-circular path until they again came between the two
grids. Again they would be shocked and be sent flying out toward the
side. Ancl again the magnet would pull them back to complete one full
circle of the chamber and be shocked again.

At each jolt from the current the deuterons would gather more energy.
This meant that they would go flying out from between the grids with
constantly increasing force and in constantly widening circles. So you get
the picture of the atomic bullets receiving shocks one right after thfe^other
from a weak electrical force. Each time the bullets receive a shock their
energy is increased and they go on, describing wider and wider circles
around the cyclotron chamber. Finally, they circle so widely that they
reach a slit in the chamber wall and go flying out into the open air. The
whole secret of the thing lies in making sure by means of the magnet that
the atomic bullets are forced to come back for successive shocks until their
energy is built up to the point where they can force their way to the exit.
Dr. Lawrence figured that to bombard any substance with his atomic bul-
lets, all he had to do was clamp this substance over the slit and let the
onrushing stream of deuterons crash into it. This then was the theory put
to the crucial test in 1934 at the University Radiation Laboratory. Dr.
Lawrence threw the switch that sent a high-powered radio transmitter
pumping energy into the cyclotron and the first experiment with the 85-
ton machine had begun.

If he and his colleagues held their collective breath during the first test,
the results soon showed that their fear$ were without grounds. Within a
short time, physicists were amazed to hear that Lawrence and his cyclo-
tron were not only changing familiar elements like platinum, into other
elements, like iridium and gold, but were actually producing substances
never before seen on earth. These were the artificially radioactive ele-
ments. Perhaps their character is best explained by illustration.

One of the experiments performed with the cyclotron involved the bom-
bardment of iron atoms with the high-speed deuterons produced by the
cyclotron. When the deuterons crashed into them with a force of about
eight million volts, the iron atoms were broken up. Some changed into

206 MATTER, ENERGY, PHYSICAL LAW

atoms of cobalt or manganese. But others were converted into a new form
of iron which, like radium, emitted streams of electrically charged par-
ticles. In other words, this new iron was radioactive. Thirty-four different
elements were subjected to bombardment with the 85-ton cyclotron and
all of them underwent a transformation, many turning into radioactive
substances. Among the artificial radioactive materials produced by the
cyclotron were sodium, phosphorus, iron, and iodine. It was even pos-
sible by bombarding bismuth to produce a degenerate form of radium,
called Radium E.

Another interesting product of these atomic bombardments was the
neutron, a particle often found in the atomic nucleus. It adds to the weight
of the nucleus but has no electrical charge, hence its name. When atoms
were smashed by the bullets from the cyclotron, they flew into two parts.
One might be an atom of a new radioactive element, and the other an
atom of a light element such as hydrogen or helium. But more often than
either of these two, a neutron would appear. When the cyclotron was
going full blast, ten billion of these particles could be liberated every
second.

While neutrons are important as building-blocks of nature, they are
also worthy of notice for their ability to destroy matter. A fast neutron
rolling along at the speed of light has tremendous penetrating power.
So great is this power, in fact, that even though the 225-ton machine is
surrounded by lead water tanks and tin cans full of water and is inside
a laboratory with thick concrete walls neutrons produced by its atomic
bombardments have been detected as far as 100 yards from the building.
When the neutrons are slowed up by passage through a sheet of paraffine,
they lose part of their penetrating power, at the same time gaining tre-
mendously in their ability to smash anything placed in their path.
Physicists have taken advantage of this phenomenon. They are using
slow neutrons for many experiments in which a high-powered sub-
atomic bullet is required.

At present the slow neutron is the bully boy being groomed for the
final day when physicists hope to break into the treasure-house of atomic
energy.

To continue his research on the fundamental problem of atomic struc-
ture Dr. Lawrence plans to build a 4900-ton cyclotron, approximately
twenty-two times as large as the 225-ton machine which is itself the
largest atom-smasher of its kind in the world. This monster would cost
from a million to a million and a half dollars. This is a great deal of
money but let's see what it would buy. . . .

TOURING THE ATOMIC WORLD 207

Dr. Lawrence points out that even the tremendously powerful atomic
bullets thrown out by the 225-ton cyclotron have not yet forced a com-
plete capitulation of the atomic citadel. They can split off only a few of
the particles of the nucleus. Before physicists can solve the fundamental
problem of the forces that bind together the atomic nucleus it is necessary
that this tight little core of the atom be completely torn apart. An atomic
"explosion" must be provoked.

. . . The laboratory in which these tremendous forces will be unleashed
for atomic study will be placed far from the campus proper. We have
already seen how the 225-ton cyclotron produces rays that pass through
thick lead tanks full of water, through the concrete sides of the Radiation
Laboratory, and out for more than 100 yards across the campus of the
University. These forces are relatively weak in comparison with those
that would be produced by a 4900-ton machine. Probably no practicable
amount of artificial sheathing would cut down the radiation reaching the
outside sufficiently. So the plans now are to place the machine and the
laboratory in a great building in Strawberry Canyon in the Berkeley
Hills. Then at least 500 feet will separate the cyclotron from its innocent
neighbors. To protect the laboratory staff from the tremendous amount
of radiation that will be produced, the machine will be surrounded by
lead water jackets 15 feet thick. It is possible also that the control room
may be placed underground so that the earth will provide an additional
buffer between the cyclotron and its operators.

In the higher energy ranges within reach of the 4900-ton cyclotron
and with the much more powerful atomic bullets produced by this tre-
mendous machine entirely new forms of radiation and entirely new sub-
stances will be produced and put to the service of mankind. Identity of
these radiations and substances can only be guessed at but certainly they
will prove of the greatest importance not only as additions to our funda-
mental knowledge of the behavior of atoms but also as contributions to
industry, biology, and medicine. It may be possible with the 4900-ton
cyclotron to transmute any element into another at will, to produce any
known substance and many new ones to order. This would give us com-
plete mastery of all the physical elements. Still it wouldn't touch the pos-
sibilities of the achievement Dr. Lawrence is really working toward: lib-
eration of the power contained in the atomic nucleus.

Let's review again the facts concerning this power. The nucleus makes
up more than 99 per cent of the mass of the atom and contains more than
99 per cent of the atom's energy. This store of energy has never been
tapped for useful purposes. Nevertheless, we know it must be tremen-
dous. Radium releases enough energy to raise its own weight in water tc

208 MATTER, ENERGY, PHYSICAL LAW

the boiling point every hour and it continues to give off this energy for
thousands of years. Nor is radium unique. Locked within the nuclei of
commoner and less expensive elements are like funds of power. At the
Radiation Laboratory Dr. Malcolm Henderson, a physicist on leave from
Princeton University, bombarded 13 grams of uranium. He found that
each uranium atom he was able to split gave off 175,000,000 electron volts
of energy. From those results he calculated that eight pounds of uranium
contain as much power as 6,300 tons of fuel oil, and that a little over a
half-pound of uranium would warm a ton of water to 3,860,000 degrees
Centigrade, or convert 386,000 tons of ice water into boiling water. If
such vast amounts of energy could be released and harnessed for practical
purposes we would never again have to worry over depletion of our sup-
plies of coal and oil. Conservation of natural resources would become but
an empty phrase that once was popular when men still depended upon
minerals for power and heat.

Now how to release this energy? You'll remember our sub-atomic
bruiser, the slow neutron. On his shoulders rest the hopes of Dr. Lawrence
and his Radiation Laboratory staff. Here is how they hope to put him to
work. First, they will build up the power in the 49Oo-ton cyclotron until it
is producing streams of deuterons or helium atoms carrying energies of
more than 100 million volts. These charged particles will be sent crashing
into some element, probably uranium at first because it has been used
before in such experiments. Under the tremendous impact of the atomic
bullets, atoms of this element will be shattered. Great clouds of slow neu-
trons will be released. With their power to destroy they will blast more
atoms of the element, releasing more neutrons to impact on and shatter
more atoms. With each of these shattering blows energy in excess of 175,-
000,000 volts will be released. Thus will be achieved the "chain reaction,"
or chain of atomic explosions, that has been hoped for and which should
be attainable with the 4900-ton cyclotron.

When I went to see Dr. Lawrence, I was a bit worried about what
might happen when this chain reaction started. After all, there would be
an almost unbelievable amount of energy released. What if they couldn't
stop the reaction and it just kept going on releasing more and more
energy? There might be a terrific outburst that would send cyclotron,
Nobel prize winner and everything else sailing up into the sky. But when
I broached this question, Dr. Lawrence just smiled and said, "Well, that's
not really such a great danger because the neutron's own properties will
protect us from such an eventuality. You see, the slow neutron has great
disintegrating power. We'll use this power to release the sub-atomic
energy. But as the explosions continue, the element we are breaking up
will become white hot. As the temperature rises, the neutrons will streak

THE DISCOVERY OF RADIUM 209

along at a constantly faster pace. As you know, a neutron loses in disinte-
grating power and gains in penetrating power as it speeds up. Pretty soon
all these neutrons released will be just passing through the atoms without
destroying them and the reaction will come to a natural conclusion. But
by that time we'll already have obtained enough energy to last us a good
long while."

'94°

The Discovery of Radium

EVE CURIE

From Madame Curie

WHILE A YOUNG WIFE KEPT HOUSE, WASHED HER
baby daughter and put pans on the fire, in a wretched laboratory
at the School of Physics a woman physicist was making the most impor-
tant discovery of modern science.

At the end of 1897 the balance sheet of Marie's activity showed two
university degrees, a fellowship and a monograph on the magnetization
of tempered steel. No sooner had she recovered from childbirth than she
was back again at the laboratory.

The next stage in the logical development of her career was the doctor's
degree. Several weeks of indecision came in here. She had to choose a
subject of research which would furnish fertile and original material. Like
a writer who hesitates and asks himself questions before settling the sub-
ject of his next novel, Marie, reviewing the most recent work in physics
with Pierre, was in search of a subject for a thesis.

At this critical moment Pierre's advice had an importance which can-
not be neglected. With respect to her husband, the young woman regarded
herself as an apprentice: he was an older physicist, much more experi-
enced than she. He was even, to put it exactly, her chief, her "boss."

210 MATTER, ENERGY, PHYSICAL LAW

But without a doubt Marie's character, her intimate nature, had a great
part in this all-important choice. From childhood the Polish girl had car-
ried the curiosity and daring of an explorer within her. This was the in-
stinct that had driven her to leave Warsaw for Paris and the Sorbonne,
and had made her prefer a solitary room in the Latin Quarter to the
Dluskis' downy nest. In her walks in the woods she always chose the
wild trail or the unfrequented road.

At this moment she was like a traveler musing on a long voyage. Bent
over the globe and pointing out, in some far country, a strange name that
excites his imagination, the traveler suddenly decides to go there and no-
where else: so Marie, going through the reports of the latest experimental
studies, was attracted by the publication of the French scientist Henri Bec-
querel of the preceding year. She and Pierre already knew this work; she
read it over again and studied it with her usual care.

After Roentgen's discovery of X rays, Henri Poincare conceived the
idea of determining whether rays like the X ray were emitted by "flu-
orescent" bodies under the action of light. Attracted by the same problem,
Henri Becquerel examined the salts of a "rare metal," uranium. Instead
of finding the phenomenon he had expected, he observed another, alto-
gether different and incomprehensible : he found that uranium salts spon-
taneously emitted, without exposure to light, some rays of unknown na
ture. A compound of uranium, placed on a photographic plate surrounded
by black paper, made an impression on the plate through the paper. And,
like the X ray, these astonishing "uranic" salts discharged an electroscope
by rendering the surrounding air a conductor.

Henri Becquerel made sure that these surprising properties were not
caused by a preliminary exposure to the sun and that they persisted when
the uranium compound had been maintained in darkness for several
months. For the first time, a physicist had observed the phenomenon to
which Marie Curie was later to give the name of radioactivity. But the
nature of the radiation and its origin remained an enigma.

Becquerel's discovery fascinated the Curies. They asked themselves
whence came the energy — tiny, to be sure — which uranium compounds
constantly disengaged in the form of radiation. And what was the nature
of this radiation? Here was an engrossing subject of research, a doctor's
thesis! The subject tempted Marie most because it was a virgin field:
Becquerel's work was very recent and so far as she knew nobody in the
laboratories of Europe had yet attempted to make a fundamental study
of uranium rays. As a point of departure, and as the only bibliography,
there existed some communications presented by Henri Becquerel at the

THE DISCOVERY OF RADIUM 211

Academy of Science during the year 1896. It was a leap into great adven-
ture, into an unknown realm.

There remained the question o£ where she was to make her experi-
ments— and here the difficulties began. Pierre made several approaches to
the director of the School of Physics with practically no results: Marie was
given the free use of a little glassed-in studio on the ground floor of the
school. It was a kind of storeroom, sweating with damp, where unused
machines and lumber were put away. Its technical equipment was rudi-
mentary and its comfort nil.

Deprived of an adequate electrical installation and of everything that
forms material for the beginning of scientific research, she kept her pa-
tience, sought and found a means of making her apparatus work in this
hole.

It was not easy. Instruments of precision have sneaking enemies: humid-
ity, changes of temperature. Incidentally the climate of this little work-
room, fatal to the sensitive electrometer, was not much better for Marie's
health. But this had no importance. When she was cold, the young woman
took her revenge by noting the degrees of temperature in centigrade in
her notebook. On February 6, 1898, we find, among the formulas and
figures: "Temperature here 6° '25. [About 44° Fahrenheit.] Six de-
grees . . . !" Marie, to show her disapproval, added ten little exclamation
points.

The candidate for the doctor's degree set her first task to be the measure-
ment of the "power of ionization" of uranium rays — that is to say, their
power to render the air a conductor of electricity and so to discharge an
electroscope. The excellent method she used, which was to be the key to
the success of her experiments, had been invented for the study of other
phenomena by two physicists well known to her: Pierre and Jacques
Curie. Her technical installation consisted of an "ionization chamber," a
Curie electrometer and a piezoelectric quartz.

At the end of several weeks the first result appeared: Marie acquired
the certainty that the intensity of this surprising radiation was propor-
tional to the quantity of uranium contained in the samples under exam-
ination, and that this radiation, which could be measured with precision,
was not affected either by the chemical state of combination of the ura-
nium or by external factors such as lighting or temperature.

These observations were perhaps not very sensational to the uninitiated,
but they were of passionate interest to the scientist. It often happens in
physics that an inexplicable phenomenon can be subjected, after some in-
vestigation, to laws already known, and by this very fact loses its interest
for the research worker. Thus, in a badly constructed detective story, if we

212 MATTER, ENERGY, PHYSICAL LAW

are told in the third chapter that the woman of sinister appearance who
might have committed the crime is in reality only an honest little house-
wife who leads a life without secrets, we feel discouraged and cease to
read.

Nothing of the kind happened here. The more Marie penetrated into
intimacy with uranium rays, the more they seemed without precedent,
essentially unknown. They were like nothing else. Nothing affected them.
In spite of their very feeble power, they had an extraordinary individuality.

Turning this mystery over and over in her head, and pointing toward
the truth, Marie felt and could soon affirm that the incomprehensible
radiation was an atomic property. She questioned: Even though the phe-
nomenon had only been observed with uranium, nothing proved that
uranium was the only chemical element capable of emitting such radia-
tion. Why should not other bodies possess the same power? Perhaps it
was only by chance that this radiation had been observed in uranium first,
and had remained attached to uranium in the minds of physicists. Now it
must be sought for elsewhere. . . .

No sooner said than done. Abandoning the study of uranium, Marie
undertook to examine all \nown chemical bodies, either in the pure state
or in compounds. And the result was not long in appearing: compounds
of another element, thorium, also emitted spontaneous rays like those of
uranium and of similar intensity. The physicist had been right: the sur-
prising phenomenon was by no means the property of uranium alone, and
it became necessary to give it a distinct name. Mme Curie suggested the
name of radioactivity. Chemical substances like uranium and thorium,
endowed with this particular "radiance," were called radio elements.

Radioactivity so fascinated the young scientist that she never tired of
examining the most diverse forms of matter, always by the same method.
Curiosity, a marvelous feminine curiosity, the first virtue of a scientist,
was developed in Marie to the highest degree. Instead of limiting her ob-
servation to simple compounds, salts and oxides, she had the desire to
assemble samples of minerals from the collection at the School of Physics,
and of making them undergo almost at hazard, for her own amusement,
a kind of customs inspection which is an electrometer test. Pierre ap-
proved, and chose with her the veined fragments, hard or crumbly, oddly
shaped, which she wanted to examine.

Marie's idea was simple — simple as the stroke of genius. At the cross-
roads where Marie now stood, hundreds of research workers might have
remained, nonplussed, for months or even years. After examining all
known chemical substances, and discovering — as Marie had done — the
radiation of thorium, they would have continued to ask themselves in

THE DISCOVERY OF RADIUM 213

vain whence came this mysterious radioactivity. Marie, too, questioned
and wondered. But her surprise was translated into fruitful acts. She had
used up all evident possibilities. Now she turned toward the unplumbed
and the unknown.

She knew in advance what she would learn from an examination of
the minerals, or rather she thought she knew. The specimens which con-
tained neither uranium nor thorium would be revealed as totally "inac-
tive." The others, containing uranium or thorium, would be radioactive.

Experiment confirmed this prevision. Rejecting the inactive minerals,
Marie applied herself to the others and measured their radioactivity. Then
came a dramatic revelation: the radioactivity was a great deal stronger
than could have been normally foreseen by the quantity of uranium or
thorium contained in the products examined!

"It must be an error in experiment," the young woman thought; for
doubt is the scientist's first response to an unexpected phenomenon.

She started her measurements over again, unmoved, using the same
products. She started over again ten times, twenty times. And she was
forced to yield to the evidence: the quantities of uranium found in these
minerals were by no means sufficient to justify the exceptional intensity
of the radiation she observed.

Where did this excessive and abnormal radiation come from? Only
one explanation was possible: the minerals must contain, in small quan-
tity, a much more powerfully radioactive substance than uranium and
thorium.

But what substance? In her preceding experiments, Marie had already
examined all \nown chemical elements.

The scientist replied to the question with the sure logic and the mag-
nificent audaciousness of a great mind: The mineral certainly contained
a radioactive substance, which was at the same time a chemical element
unknown until this day: a new element.

A new element! It was a fascinating and alluring hypothesis — but still
a hypothesis. For the moment this powerfully radioactive substance existed
only in the imagination of Marie and of Pierre. But it did exist there. It
existed strongly enough to make the young woman go to see Bronya one
day and tell her in a restrained, ardent voice:

"You know, Bronya, the radiation that I couldn't explain comes from
a new chemical element. The element is there and I've got to find it. We
are sure! The physicists we have spoken to believe we have made an error
in experiment and advise us to be careful. But I am convinced that I am
not mistaken."

214 MATTER, ENERGY, PHYSICAL LAW

These were unique moments in her unique life. The layman forms a
theatrical— and wholly false— idea of the research worker and of his dis-
coveries. "The moment of discovery" does not always exist: the scientist's
work is too tenuous, too divided, for the certainty of success to crackle out
suddenly in the midst of his laborious toil like a stroke of lightning, daz-
zling him by its fire. Marie, standing in front of her apparatus, perhaps
never experienced the sudden intoxication of triumph. This intoxication
was spread over several days of decisive labor, made feverish by a mag-
nificent hope. But it must have been an exultant moment when, convinced
by the rigorous reasoning of her brain that she was on the trail of new
matter, she confided the secret to her elder sister, her ally always. . . .
Without exchanging one affectionate word, the two sisters must have lived
again, in a dizzying breath of memory, their years of waiting, their mutual
sacrifices, their bleak lives as students, full of hope and faith.

It was barely four years before that Marie had written:

Life is not easy for any of us. But what of that? We must have persever-
ance and above all confidence in ourselves. We must believe that we are
gifted for something, and that this thing, at whatever cost, must be attained.

That "something" was to throw science upon a path hitherto unsus-
pected.

In a first communication to the Academy, presented by Prof. Lipp-
mann and published in the Proceedings on April 12, 1898, "Marie Sklodov-
ska Curie" announced the probable presence in pitchblende ores of a new
element endowed with powerful radioactivity. This was the first stage of
the discovery of radium.

By the force of her own intuition the physicist had shown to herself
that the wonderful substance must exist. She decreed its existence. But its
incognito still had to be broken. Now she would have to verify hypothesis
by experiment, isolate this material and see it. She must be able to
announce with certainty: "It is there."

Pierre Curie had followed the rapid progress of his wife's experiments
with passionate interest. Without directly taking part in Marie's work, he
had frequently helped her by his remarks and advice. In view of the
stupefying character of her results, he did not hesitate to abandon his study
of crystals for the time being in order to join his efforts to hers in the search
for the new substance.

Thus, when the immensity of a pressing task suggested and exacted
collaboration, a great physicist was at Marie's side — a physicist who was
the companion of her life. Three years earlier, love had joined this excep-

THE DISCOVERY OF RADIUM 215

tional man and woman together — love, and perhaps some mysterious fore-
knowledge, some sublime instinct for the work in common.

The valuable force was now doubled. Two brains, four hands, now
sought the unknown element in the damp little workroom in the Rue
Lhomond. From this moment onward it is impossible to distinguish each
one's part in the work of the Curies. We know that Marie, having chosen
to study the radiation of uranium as the subject of her thesis, discovered
that other substances were also radioactive. We know that after the ex-
amination of minerals she was able to announce the existence of a new
chemical element, powerfully radioactive, and that it was the capital im-
portance of this result which decided Pierre Curie to interrupt his very
different research in order to try to isolate this element with his wife. At
that time — May or June, 1898 — a collaboration began which was to last
for eight years, until it was destroyed by a fatal accident.

We cannot and must not attempt to find out what should be credited to
Marie and what to Pierre during these eight years. It would be exactly
what the husband and wife did not want. The personal genius of Pierre
Curie is known to us by the original work he had accomplished before this
collaboration. His wife's genius appears to us in the first intuition of dis-
covery, the brilliant start; and it was to reappear to us again, solitary, when
Marie Curie the widow unflinchingly carried the weight of a new science
and conducted it, through research, step by step, to its harmonious ex-
pansion. We therefore have formal proof that in the fusion of their two
efforts, in this superior alliance of man and woman, the exchange was
equal.

Let this certainly suffice for our curiosity and admiration. Let us not
attempt to separate these creatures full of love, whose handwriting alter-
nates and combines in the working notebooks covered with formulae,
these creatures who were to sign nearly all their scientific publications to-
gether. They were to write "We found" and "We observed"; and when
they were constrained by fact to distinguish between their parts, they were
to employ this moving locution :

Certain minerals containing uranium and thorium (pitchblende, chal-
colite, uranite) are very active from the point of view of the emission of
Becquerel rays. In a preceding communication, one of us showed that their
activity was even greater than that of uranium and thorium, and stated the
opinion that this effect was due to some other very active substance contained
in small quantity in these minerals.

(Pierre and Marie Curie: Proceedings of the Academy of Science, July 18,
1898.)

216 MATTER, ENERGY, PHYSICAL LAW

Marie and Pierre looked for this "very active" substance in an ore of
uranium called pitchblende, which in the crude state had shown itself to
be four times more radioactive than the pure oxide of uranium that could
be extracted from it. But the composition of this ore had been known for
a long time with considerable precision. The new element must therefore
be present in very small quantity or it would not have escaped the notice
of scientists and their chemical analysis.

According to their calculations — "pessimistic" calculations, like those
of true physicists, who always take the less attractive of two probabilities
— the collaborators thought the ore should contain the new element to a
maximum quantity of one per cent. They decided that this was very little.
They would have been in consternation if they had known that the radio-
active element they were hunting down did not count for more than a
millionth part of pitchblende ore.

They began their prospecting patiently, using a method of chemical
research invented by themselves, based on radioactivity; they separated all
the elements in pitchblende by ordinary chemical analysis and then
measured the radioactivity of each of the bodies thus obtained. By suc-
cessive eliminations they saw the "abnormal" radioactivity take refuge in
certain parts of the ore. As they went on, the field of investigation was
narrowed. It was exactly the technique used by the police when they
search the houses of a neighborhood, one by one, to isolate and arrest a
malefactor.

But there was more than one malefactor here: the radioactivity was
concentrated principally in two different chemical fractions of the pitch-
blende. For M. and Mme Curie it indicated the existence of two new ele-
ments instead of one. By July 1898 they were able to announce the dis-
covery of one of these substances with certainty.

"You will have to name it," Pierre said to his young wife, in the same
tone as if it were a question of choosing a name for little Irene.

The one-time Mile Sklodovska reflected in silence for a moment. Then,
her heart turning toward her own country which had been erased from the
map of the world, she wondered vaguely if the scientific event would be
published in Russia, Germany and Austria — the oppressor countries — and
answered timidly :

"Could we call it 'polonium'?"

In the Proceedings of the Academy for July 1898 we read:

We believe the substance we have extracted from pitchblende contains a
metal not yet observed, related to bismuth by its analytical properties. If the
existence of this new metal is confirmed we propose to call it polonium,
from the name of the original country of one of us.

THE DISCOVERY OF RADIUM 217

The choice of this name proves that in becoming a Frenchwoman and
a physicist Marie had not disowned her former enthusiasms. Another
thing proves it for us : even before the note "On a New Radioactive Sub-
stance Contained in Pitchblende" had appeared in the Proceedings of the
Academy, Marie had sent the manuscript to her native country, to that
Joseph Boguski who directed the little laboratory at the Museum of In-
dustry and Agriculture where she had made her first experiments. The
communication was published in Warsaw in a monthly photographic
review called Swiatlo almost as soon as in Paris. . . .

We find another note worthy of remark.

It was drawn up by Marie and Pierre Curie and a collaborator called
G. Bemont. Intended for the Academy of Science, and published in the
Proceedings of the session of December 26, 1898, it announced the existence
of a second new chemical element in pitchblende.

Some lines of this communication read as follows:

The various reasons we have just enumerated lead us to believe that the
new radioactive substance contains a new element to which we propose to
give the name of RADIUM.

The new radioactive substance certainly contains a very strong proportion
of barium; in spite of that its radioactivity is considerable. The radioactivity
of radium therefore must be enormous.

The Taming of Energy

GEORGE RUSSELL HARRISON

From Atoms in Action

YESTERDAY WAS SUNNY OR CLOUDY, A
June day or a day in December, enough energy fell on the earth
during that twenty-four hours to serve humanity for several centuries —
enough to keep the world's furnaces roasting and its refrigerators icy, to
spin its wheels and refine its ores, and to fill for several hundred years every
other present need for power. The wheels of civilization are kept turning
by energy; and all this energy, whether we draw it from a gallon of gaso-
line, a ton of coal, or a pound of butter, has come to us from the sun.

So long as the sun keeps shining we appear to have little cause to worry
about running out of energy, and the best evidence indicates that our pow-
erhouse in the heavens will still be glowing brilliantly a billion years from
now. Unfortunately, however, most of the energy we are now using came
from the sun in ages past, and we are drawing heavily on the earth's sav-
ings account of coal and oil instead of using our current energy income.
Even though the sun sends us two hundred thousand times as much power
as we use, most of this slips through our fingers, because we have not yet
learned how to convert sunlight efficiently into those forms of energy
which are useful for civilized living.

Select on a map any convenient desert, and look at an area twenty miles
square — an area which would about cover the sprawling environs of a
great city. Year after year enough sunlight is lavished on this small sandy
waste to satisfy perpetually the power needs of the entire population of the
United States at the present rate of power consumption. In fact, grimy
miners digging six thousand tons of coal from the gloomy depths of the
earth obtain only an amount of energy equivalent to that swallowed on a
sunny day by a single square mile of land or sea.

Almost every material problem of living turns out in the last analysis
to be a problem of the control of energy. The householder, when he has

218

THE TAMING OF ENERGY 219

paid his bills for fuel and electricity, is likely to consider that he has taken
care of his energy requirements for the month, yet each bill from the gro-
cer or the milliner is quite as truly a bill for energy. We do not buy a bas-
ket of strawberries for the carbon, oxygen, and nitrogen atoms they con-
tain, but for the energy stored by these atoms when they join together in
molecules to form sugars, starches, flavors, and vitamines. That part of the
cost of a lady's hat which does not represent business acumen on the part
of the milliner is for stored and directed energy — the atoms of matter of
which the hat is composed are permanent, and will still exist when the hat
has been discarded and burned. Only energy and knowledge of how to
apply it are needed to re-create a hat from its smoke and ashes!

Even such materials as gold, silver, and copper represent true wealth
only as they represent the energy required to find, collect, and purify these
metals. Our supply of matter on earth is not changing appreciably, for
although a little hydrogen and helium leak off from the top of the atmos-
phere, far more matter than we lose in this way is brought to the earth by
meteorites. Iron may rust or be scattered, but it cannot be lost so long as
sufficient energy remains to reconcentrate and re-refine it. Many a mine
long abandoned as worthless has brought in a fortune when cheaper power
or a more efficient concentrating process has made worth while the recov-
ery of further metal from its scrap-heap. Only energy is needed to gather
as much of every material as we may need from the air, the land, or the
sea.

Energy is wealth, and in the case of apprenticed sunlight, wealth of a
particularly desirable kind, for it is freshly created and does not involve
robbing the poor, taxing the rich, or despoiling the earth of materials which
may be needed by our descendants as much as by ourselves. Yet this energy
is free — to him who can discover how to capture and control it.

The scientist who is most concerned with the investigation and control
of energy is the physicist. In his researches on energy the physicist works
very closely with the chemist, who is interested primarily in matter. Matter
and energy are always closely related; and physics and chemistry, orig-
inally a single science called natural philosophy, can never be separated
completely, for they are the twin sciences which deal with the fundamental
structure of our physical universe.

The chemist gathers the minerals and fibers and oils which he finds in
nature, reduces them to the elementary atoms of which they are composed,
and then causes these atoms to recombine into thousands of new kinds of

220 MATTER, ENERGY, PHYSICAL LAW

molecules, thus forming new perfumes and dyes, new flavors and fabrics
and drugs.

The physicist, however, takes apart the very atoms themselves, sending
through wires the electrons which he thus collects, and operating with
them his telephones and X-ray tubes and television outfits. Or he may
induce the atoms to emit light rays of strange new colors, rays which he
bends with lenses cleverly designed to enable him to discern objects which
are too dark or small or transparent otherwise to be seen.

As the physicist has gradually learned to control the grosser forms of
energy such as heat and sound, he has been led to probe deeper and deeper
into nature in studying the behavior of energy in its finer and more subtle
forms, such as light and electricity and magnetism. He has now succeeded
in penetrating down through the atom into its tiny nucleus or core, and
one of his principal interests at the moment (though by no means the only
one, nor necessarily the most important one) is to take sample atom cores
apart to see what they are made of and how they are put together. The
atom is being taken to pieces quite literally, for when one of the modern
"atom-smashing" devices is put into operation the atomic debris comes
flying out like dirt from a gopher hole in which a very industrious puppy
is scratching.

The scientist who appears preoccupied with the center of the atom is
burrowing after the key to the structure of matter and energy, not because
he expects to tap the energy in the atom, but because he knows that before
nature can be controlled she must be understood. The physicist who is
engaged in "pure" or fundamental research is attempting to understand
nature. The applied physicist is attempting to control nature. The two
kinds of investigators try to keep in close collaboration, but physics is a vast
science which ranges from such theoretical subjects as Relativity to such
practical applications as the phonograph, as the interests of its workers
have ranged from those of Einstein to those of Edison.

. . . "Atom smashing" (using the term broadly to cover fundamental
research into the structure of matter and energy) pays astonishing divi-
dends— not a mere five per cent, nor one hundred per cent, but hundiyds
of times the original investment. This is not fanciful romanticism, but
stark bookkeeping which realistic corporations, headed by typical American
business men, have many times demonstrated to their stockholders.

The scientist, like the artist, creates something new merely by rearrange-
ment of the old. An industry that gets its profits from digging coal or
pumping oil or felling timber is constantly depleting its resources. An
industry that rests on a physical discovery gets its profits through fresh
creation.

THE TAMING OF ENERGY 221

Since wealth consists ultimately of the control of matter and energy, the
wealth level of mankind slowly rises as science learns to capture a con-
stantly growing fraction of the energy that is available and turn it more
effectively to useful ends. A factory worker in the United States is paid
several times as much in real wages as his predecessor received a generation
ago. While management may justly claim credit for this improvement, it
was made possible only by utilizing technological achievements resting on
scientific discoveries, which made the labor of each worker more produc-
tive. For the wages he received for one hour of labor in the middle 1930*5
a factory worker in Italy could buy a certain amount of food, a similar
worker in Great Britain could buy twice as much, but a worker in the
United States could buy four times as much. Economists agree that tech-
nological development and scientific discovery have been responsible for
this higher level of plenty in the United States. Science is a great agency
for social betterment, for the victories over nature which result from its
application make possible increased wages and profits and reduced prices
at the same time.

Experience has shown no better way of eliminating poverty than by well-
directed "atom smashing." Poverty can best be abolished by replacing it
with wealth; and the systematic investigation of matter and energy without
regard to immediate practical ends has turned out to be the most direct
road to social riches. In the long run digging for truth has always proved
not only more interesting, but more profitable, than digging for gold. If
urged on by the love of digging, one digs deeper than if searching for some
particular nugget. Practicality is inevitably short-sighted, and is self-handi-
capped by the fact that it is looking so hard for some single objective that
it may miss much that nature presents to one who is purposefully digging
for whatever may turn up.

Each dweller in the United States is now served, on the average, by
energy equivalent to that which could be provided by thirty slaves such as
sweated at the command of an ancient Egyptian king. In making this
much energy available, science has contributed only a small fraction of
what it can contribute. Human beings can be made at least twenty thou-
sand times as wealthy as they are today; but only the fundamental inves-
tigation of nature, such as is involved in "atom smashing," will show how.

3

Energy can neither be created nor destroyed (except as it can be changed
into matter under certain extreme conditions, and produced from
matter), but it can appear in any of a dozen or more forms. If the physicist
succeeds in backing a bit of energy into a corner, so to speak, he usually

222 MATTER, ENERGY, PHYSICAL LAW

expects il to disappear like a witch in a fairy tale, and to reappear in an
entirely different form. By careful study of many typical situations he has
learned where to lie in wait for the reappearance of the energy so that he
can pounce on it in its new guise, or, if it stay hidden, ferret out its place
of concealment. All of our most useful machines, such as electric motors
and kitchen ranges and cameras, are merely clever devices for beguiling
energy of one form into changing itself into another form which we desire
to use. By touching a match to a gallon of gasoline we can cause the
chemical energy which the gasoline contains to be transformed into thermal
energy; but if instead we use a spark plug in an automobile cylinder, much
of the thermal energy, when it appears, will find itself harnessed to perform
mechanical work.

The most useful forms of energy for practical purposes are those we call
heat, sound, and light, and the mechanical, electrical, magnetic, chemical,
and gravitational forms. When we have learned how to convert energy
from any one of these forms directly into any other at will, without letting
much energy escape in the process, the millennium will have arrived so
far as the cost of living is concerned.

If, for example, we knew how to convert electrical energy directly into
light, the problem of "cold light" would be solved. At present we must use
indirect means, as in the incandescent lamp, where electrical energy is
forced to heat a tungsten filament and thus is turned into heat energy.
When heat has set the filament glowing some of its energy is transformed
into useful light as a by-product, but nine-tenths of the energy is wasted as
invisible radiation, boosting our electric light bills to ten times what they
should be.

An example of the many useful applications which often result from the
discovery of a new way of transforming one form of energy into another
is given by the piezo-electric crystal. The brothers Pierre and Paul Curie
found in 1880 that sensitive crystals of certain types, such as quartz and
Rochelle salt, shrink and swell when given electric shocks. Thus was dis-
covered a new method of changing electrical energy into mechanical
energy. The crystals were found also to generate electric charges on their
surfaces when squeezed or stretched, so they could be used to convert
mechanical energy back into the electrical form as well. The Curie brothers
were academic physicists, interested chiefly in digging out facts (Pierre,
with his wife Marie, later discovered radium), so they made no use of their
discovery. It lay unapplied until 1917, when, during the World War,
another physicist decided that crystals might be useful for detecting the
sound waves given out by submarines. His work was so successful that it
suggested further fields for investigation, and later we shall find piezo-

THE TAMING OF ENERGY 223

electric crystals being used for such diverse purposes as keeping radio
broadcasting stations tuned to the proper frequency, serving as micro-
phones for changing sound waves into electrical waves, and forming
wave-filters which keep separate more than two hundred telephone conver-
sations passing simultaneously over the same pair of wires. These accom-
plished crystals also make excellent phonograph pickups, can be used as
telephone transmitters and receivers, and operate the most accurate clocks
in the world, which tick 100,000 times a second. Again, by tickling such
crystals electrically at high frequency they can be made to emit super-
sounds, which are of value for cracking crude oil to increase its yield of
gasoline, for precipitating smoke, for detecting icebergs or other obstruc-
tions at sea, and even for speeding up the pickling of cucumbers I

The delay of thirty-seven years in putting the piezo-electric crystal to
work occurred because good methods of applying rapid electric shocks to
the crystal were not available until the electronic vacuum tube was in-
vented, which in turn waited on the discovery of the electron. Thus the
application of one important discovery is often forced to await the birth
of another.

Man's physical developments involve special transformations of energy
from one form to another — as in telephony, where sound vibrations are
changed into electrical vibrations, carried through space on waves or over
wires, and then changed back into sound vibrations; or in television, where
the same is done for visual images. But fundamental to all such processes
is the transportation and storage of energy in bulk.

4

Transporting energy from place to place keeps millions of men busy.
Most energy is transported in one of three ways : in coal carried by ships
or freight cars; in oil carried by ships, tank cars, or pumped through pipe
lines; or sent over wires as electrical power. More than half our energy is
carried in coal. Electrical power is more convenient to use than any other
kind, but even when energy is ultimately to be delivered in electrical form
it is cheapest at present to carry it locked in coal or oil for as much of its
journey as possible.

In the United States there are 110,000 miles of pipes through which black
oil flows, sometimes for more than a thousand miles on a single journey;
65,000 additional miles of pipe carry natural gas for fuel; and together
these buried pipe lines form a transportation system almost three-quarters
as long as all the railroad tracks of the country. About half as much energy
as is carried by oil and gas flows through wires, carried by electric currents

224 MATTER, ENERGY, PHYSICAL LAW

consisting of countless electrons sent swinging Irom one copper atom to
the next.

To carry energy to its user costs much more than to dig it out of the
ground as coal or to scoop it up with turbine blades from a waterfall.
Though a ton of coal costs less than four dollars at the mine, delivered to
the ultimate user it may cost four times as much. Electrical energy delivered
in the home now costs on the average five and a half cents a kilowatt hour,
more than ten times its cost to produce in wholesale lots at a steam plant
near a coal mine. There is great need for development of cheaper electrical
methods of transmitting power. Standard engineering methods are begin-
ning to be found insufficient — new methods must be provided by applying
physics anew.

At present electric power cannot be piped economically farther than a
few hundred miles unless expensive special equipment is used; only when
a tremendous load of power can be sold is it economical to provide this
equipment. The electrical engineer delivering his kilowatts is in much the
situation of a small boy carrying home sugar from the grocery store in a
paper sack with a hole in its bottom which lets the sugar trickle slowly
away. Since the engineer cannot now afford to plug the hole, only those
persons can afford to buy electrical sugar whose homes are within a few
hundred miles of an electrical power store.

It has long been known that the most efficient way to send power over
wires of a given size is to keep the flow of electric current as low as possible,
and make the voltage, or electrical pressure of the line, as great as possible,
Engineers have a working rule which says that a power line should be
operated at such a high voltage that 1000 volts-is provided for each mile the
power is carried. Since 350,000 volts is about the economical upper limit
of voltage practical on present power lines, this sets a 350-mile limit:

In 1941 the longest power line stretched 270 miles from Boulder Dam to
Los Angeles. To carry energy from such great water-power developments
as Tennessee Valley to the large cities where power is most needed,
methods of using higher voltages must "be provided. But raising the voltage
of a standard power line above 350,000 volts may cause the bottom to drop
out of the electrical sugar bag — the air, the line, and the insulators refuse to
co-operate longer in keeping the electrical flow intact.

Long-distance transmission lines now operate with alternating current,
briefly written A.C. Electricity is first pushed into one wire of* the line and
pulled from the other, and then the push and pull are reversed. Pushes
and pulls are usually alternated 120 times in a second, giving 6o-cycle A.C.
Power can also be transmitted with direct current (D.-C.) by pumping
electrons continuously into one wire*and out of the other, and it* is known

THE TAMING OF ENERGY 225

that with such D.C. transmission much less electricity leaks from a line
than with A.C. Short lines operating at more than a million volts D.C.
have been used experimentally to carry power. However, the transformers
which give the most convenient means of stepping electricity up from a
low voltage to a high voltage, or stepping it down again, operate only
with alternating current. For safety, power must be generated and used
at low voltages; yet for economy it must be sent over a long line at high
voltage. This combination of necessities sets a pretty dilemma.

Here the electronic vacuum tube enters the picture; and with its aid the
problem may well be solved. With tubes of one type direct current can be
changed to alternating current at any voltage. By using tubes of a second
type alternating current can be changed to direct. Such tubes should make
it possible to generate alternating current power, step this up to high
voltage with transformers, change the power to D.C. with a vacuum tube
and send it over the long-distance power line, at the far end change it back
to A.C. with another vacuum tube, and then step it down with a trans-
former to the desired voltage for use. This process of sidestepping nature's
obstacles, which might be described in football terms as a double lateral
pass with a forward pass between, sounds complex, but actually it is simple
once the vacuum tubes have been put into reliable working order.. A trial
installation of this sort has been kept in satisfactory operation by the
General Electric Company in Schenectady for several years.

An entirely different attack on the problem of high-voltage D.C. power
transmission has been suggested by the work of an atom-smashing
physicist, Dr. Robert J. Van de Graaff, and his collaborators. They were
interested, not so much in developing a new means of transmitting power,
as in perfecting a high-voltage machine which would generate 5,000,000
volts with which to hurl electrical bullets against the cores of atoms which
were to be smashed. In Van de Graaff's generator, electrons are sprayed
against wide rubber belts. To these belts the electrons stick, and by them
are carried up into a large metal sphere, which they gradually charge with
electricity. The sphere is carefully insulated from the ground by a sup-
porting column thirty feet high, and so smooth and round is this sphere
that electricity can leak into the air from it but slowly. If electrons are
pumped indefinitely into the sphere its electrical pressure rises until finally
a voltage is reached which the air can resist no longer, and a great flash of
artificial lightning jumps between the sphere and any near-by object con-
nected to the ground. With -such a generator several million volts might
be applied directly to a power line, no transformers would be needed at the
beginning of the line, and extremely weak direct currents would suffice
to transmit large amounts of power with little loss.

226 MATTER, ENERGY, PHYSICAL LAW

Scientists have envisaged long D.C. lines consisting of a pipe, buried in
the earth with a wire stretched down its center, carrying power from great
hydraulic turbo-generators, or from steam plants located near coal mines,
to any city in the country. The pipe might be filled with carbon tetra-
chloride vapor, or with the Freon vapor used in refrigerators, to reduce
leakage of electricity between the wire and the pipe. It has even been sug-
gested that the pipe might be evacuated over its whole length of more than
a thousand miles, for electricity cannot leak across a well-evacuated space.
To obtain a suitable vacuum thousands of high-speed pumps would have
to be kept sucking on the pipe like piglets on a myriad-breasted mother
pig. At present such a project is perhaps visionary, but it illustrates how
the practicability of an engineering scheme may hinge on new develop-
ments of physics — in this case, on a high-voltage generator and a more
efficient vacuum pump.

Must wires always be used to carry electric power from place to place,
or could rays be used instead? Dreamers have long talked of powerful
rays which could be focused on distant machinery to which energy was
thus supplied. Keeping airplanes aloft without fuel is a favorite applica-
tion. At present no rays energetic enough for this purpose and at the same
time available in quantity are known to scientists. Radio waves and light
waves are more suited to such comparatively dainty tasks as carrying
messages than to feeding engines with power. Machinery can be operated
with the energy contained in rays of sunlight, to be sure, but the power
these carry is insufficiently concentrated to be worth using at present, even
when available. Rays of more concentrated types have either insufficient
penetrating power to travel far through the air, or are uncontrollable, or
are available only in very small quantities. Energy can be most readil)
controlled by giving it matter to cling to when it is to be stored, concen-
trated, or carried from place to place with little loss.

5

To store energy for future use is much more difficult than to release
energy already stored in matter. When fuel is burned, the chemical energy
stored in it is released as heat energy; but the reverse process— unburning
a gallon of gasoline or a cord of wood — is very slow and difficult. Nature
unburns wood when she uses sunlight in plants to release carbon atoms
from the carbon dioxide molecules which the leaf has picked up, wafted
through the air from some long-forgotten fire. Man has not yet learned to
imitate nature in this regard, though he is beginning to get some clues as
to how the job is done.

One can store energy mechanically, as by winding a clock or bending a

THE TAMING OF ENERGY 227

bow; electrically, as by charging a condenser; gravitationally, as by pump-
ing water into a high reservoir; thermally, as in a hot water bottle; chem-
ically, as by charging a storage battery or growing a tree; and in many
other ways. All involve associating energy with matter.

In comparing storage processes a most important question is, How much
energy can be packed into each pound of matter? We can get an idea of
the energy-holding capacity of matter by seeing how much energy can be
released from a pound of each of a number of fuels; this energy can readily
be evaluated in terms of how long a pound of the fuel would keep a
6o-watt incandescent lamp burning if all its energy were converted into
electric power. Thus, a pound of wood would keep the lamp alight for
about 200 hours, a pound of coal for twice as long, a pound of gasoline
for 900 hours. Hydrogen is one of the best energy-storing substances obtain-
able, for in a pound of this gas is stored enough energy to keep the lamp
bright for nearly 2700 hours.

Any method of producing such fuels is a method of storing energy in
chemical form; and chemical storage, in which the energy is tucked
between atoms when these are grouped together to form molecules, appears
to be the best of any practical method now available to store energy with
little weight. Even fuels are heavier energy-storage reservoirs than we
would like, however; witness the concern of the aviator whose two tons
of gasoline must carry him across the Atlantic Ocean.

Any youth who wishes to win fame and fortune through scientific
discovery, but who cannot think of anything which needs discovering,
would do well to turn his attention to the problem of storing energy lightly.
If he could invent a device into which electrical energy could be fed, which
would store this energy chemically and later release it again as electrical
energy, his fortune might be made — if the device was light enough. Such a
device is, of course, merely a storage battery; but all present storage bat-
teries, though extremely efficient, are far too heavy to be used for anything
but odd jobs such as starting automobiles. One pound of ordinary lead
storage battery, when fully charged, holds less than one-twentieth as much
energy as is contained in a pound of gasoline.

If a storage battery weighing less than one-tenth as much as present bat-
teries were to become available, the electric automobile would probably
supersede the gasoline motor car almost immediately. What magic does
the heavy lead atom, now used for almost all storage of electrical energy,
possess which enables it to store energy and give this out again at the will
of the user, which is not possessed by, say, the lithium or the beryllium
atoms, weighing one-thirtieth as much ? There seems to be no reason for
supposing that a light storage battery cannot be invented, except that many

228 MATTER, ENERGY, PHYSICAL LAW

people have tried doing this, and no one has yet succeeded. Such argu-
ments have, of course, never deterred resourceful men. To invent a light
battery, the old method was to start by trying thousands of different light
materials; the new method is carefully to study nature and find how she
packs energy into atoms and molecules.

Edition of

Space, Time and Einstein*

PAUL R. HEYL

WHETHER WE UNDERSTAND IT OR NOT, WE HAVE
all heard of the Einstein theory, and failure to understand it does
not seem incompatible with the holding of opinions on the subject, some-
times of a militant and antagonistic character.

Twenty-four years have elapsed since Einstein published his first paper
on relativity, dealing principally with certain relations between mechanics
and optics. Since that time a new generation has grown up to whom pre-
Einstein science is a matter of history, not of experience. Eleven years
after his first paper Einstein published a second, in which he broadened
and extended the theory laid down in the first so as to include gravitation.
And now again, thirteen years later, in a third paper, Einstein has
broadened his theory still farther so as to include the phenomena of
electricity and magnetism,

In view of the rekindling of interest in Einstein because of the appear-
ance of his latest paper it may be worth while to reexamine and restate
the primary foundations upon which his theory rests.

The general interest taken in this subject is frequendy a matter of
wonder to those of us who must give it attention professionally, for there

* Publication approved by the Director of the Bureau of Standards of the U. S. Depart-
ment of Commerce.

SPACE, TIME AND EINSTEIN 229

are in modern physical science other doctrines which run closely second
to that of Einstein in strangeness and novelty, yet none o£ these seems to
have taken any particular hold on popular imagination.

Perhaps the reason for this is that these theories deal with ideas which
are remote from ordinary life, while Einstein lays iconoclastic hands on
two concepts about which every intelligent person believes that he really
knows something — space and time.

Space and time have been regarded "always, everywhere and by all,"
as independent concepts, sharply distinguishable from one another, with
no correlation between them. Space is fixed, though we may move about
in it at will, forward or backward, up or down; and wherever we go our
experience is that the properties of space are everywhere the same, and
are unaltered whether we are moving or stationary. Time, on the other
hand, is essentially a moving proposition, and we must perforce move
with it. Except in memory, we can not go back in time; we must go
forward, and at the rate at which time chooses to travel. We are on a
moving platform, the mechanism of which is beyond our control.

There is a difference also in our measures of space and time. Space may
be measured in feet, square feet or cubic feet, as the case may be, but time
is essentially one-dimensional. Square hours or cubic seconds are mean-
ingless terms. Moreover, no connection has ever been recognized between
space and time measures. How many feet make one hour? A meaningless
question, you say, yet something that sounds very much like it has (since
Minkowski) received the serious attention of many otherwise reputable
scientific men. And now comes Einstein, rudely disturbing these old-
established concepts and asking us to recast our ideas of space and time
in a way that seems to us fantastic and bizarre.

What has Einstein done to these fundamental concepts?

He has introduced a correlation or connecting link between what have
always been supposed to be separate and distinct ideas. In the first place,
he asserts that as we move about, the geometrical properties of space, as
evidenced by figures drawn in it, will alter by an amount depending on
the speed of the observer's motion, thus (through the concept of velocity)
linking space with time. He also asserts in the second place that the flow
of time, always regarded as invariable, will likewise alter with the motion
of the observer, again linking time with space.

For example, suppose that we, with our instruments for measuring
space and time, are located on a platform which we believe to be station-
ary. We can not be altogether certain of this, for there is no other visible
object in the universe save another similar platform carrying an observer
likewise equipped : but when we observe relative motion between our plat-

230 MATTER, ENERGY, PHYSICAL LAW

form and the other it pleases our intuition to suppose our platform at
rest and to ascribe all the motion to the other.

Einstein asserts that if this relative velocity were great enough we might
notice some strange happenings on the other platform. True, a rather
high velocity would be necessary, something comparable with the speed
of light, say 100,000 miles a second; and it is tacitly assumed that we
would be able to get a glimpse of the moving system as it flashed by.
Granting this, what would we see?

Einstein asserts that if there were a circle painted on the moving plat-
form it would appear to us as an ellipse with its short diameter in the
direction of its motion. The amount of this shortening would depend
upon the speed with which the system is moving, being quite imper-
ceptible at ordinary speeds. In the limit, as the speed approached that of
light, the circle would flatten completely into a straight line — its diameter
perpendicular to the direction of motion.

Of this shortening, says Einstein, the moving observer will be uncon-
scious, for not only is the circle flattened in the direction of motion, but
the platform itself and all it carries (including the observer) share in
this shortening. Even the observer's measuring rod is not exempt. Laid
along that diameter of the circle which is perpendicular to the line of
motion it would indicate, say, ten centimeters; placed along the shortened
diameter, the rod, being itself now shortened in the same ratio, would
apparently indicate the same length as before, and the moving observer
would have no suspicion of what we might be seeing. In fact, he might
with equal right suppose himself stationary and lay all the motion to the
account of our platform. And if we had a circle painted on our floor it
would appear flattened to him, though not to us.

Again, the clock on the other observer's platform would exhibit to us,
though not to him, an equally eccentric behavior. Suppose that other
platform stopped opposite us long enough for a comparison of clocks, and
then, backing off to get a start, flashed by us at a high speed. As it passed
we would see that the other clock was apparently slow as compared with
ours, but of this the moving observer would be unconscious.

But could he not observe our clock ?

Certainly, just as easily as we could see his.

And would he not see that our clock was now faster than his? "No,"
says Einstein. "On the contrary, he would take it to be slower."

Here is a paradox indeed! A's clock appears slow to B while at the
same time B's clock appears slow to A\ Which is right?

To this question Einstein answers indifferently:

"Either. It all depends on the point of view."

SPACE, TIME AND EINSTEIN 231

In asserting that the rate of a moving clock is altered by its motion
Einstein has not in mind anything so materialistic as the motion inter-
fering with the proper functioning of the pendulum or balance wheel.
It is something deeper and more abstruse than that. He means that the
flow of time itself is changed by the motion of the system, and that the
clock is but fulfilling its natural function in keeping pace with the altered
rate of time.

A rather imperfect illustration may help at this point. If I were traveling
by train from the Atlantic to the Pacific Coast it would be necessary for
me to set my watch back an hour occasionally. A less practical but
mathematically more elegant plan would be to alter the rate of my watch
before starting so that it would indicate the correct local time during the
whole journey. Of course, on a slow train less alteration would be
required. The point is this: that a timepiece keeping local time on the
train will of necessity run at a rate depending on the speed of the train.

Einstein applies a somewhat similar concept to all moving systems,
and asserts that the local time on such systems runs the more slowly the
more rapidly the system moves.

It is no wonder that assertions so revolutionary should encounter general
incredulity. Skepticism is nature's armor against foolishness. But there
are two reactions possible to assertions such as these. One may say: "The
man is crazy" or one may ask: "What is the evidence?"

The latter, of course, is the correct scientific attitude. To such a question
Einstein might answer laconically: "Desperate diseases require desperate
remedies."

"But," we reply, "we are not conscious of any disease so desperate as
to require such drastic treatment."

"If you are not," says Einstein, "you should be. Does your memory run
back thirty years? Or have you not read, at least, of the serious contra-
diction in which theoretical physics found itself involved at the opening
of the present century?"

Einstein's reference is to the difficulty which arose as a consequence of
the negative results of the famous Michelson-Morley experiment and
other experiments of a similar nature. The situation that then arose is
perhaps best explained by an analogy.

If we were in a boat, stationary in still water, with trains of water-
waves passing us, it would be possible to determine the speed of the
waves by timing their passage over, say, the length of the boat. If the
boat were then set in motion in the same direction in which the waves
were traveling, the apparent speed of the waves with respect to the boat
would be decreased, reaching zero when the boat attained the speed of

232 MATTER, ENERGY, PHYSICAL LAW

the waves; and if the boat were set in motion in the opposite direction
the apparent speed of the waves would be increased.

If the boat were moving with uniform speed in a circular path, the
apparent speed of the waves would fluctuate periodically, and from the
magnitude of this fluctuation it would be possible to determine the speed
of the boat.

Now the earth is moving around the sun in a nearly circular orbit with
a speed of about eighteen miles per second, and at all points in this orbit
light waves from the stars are constantly streaming by. The analogy of
the boat and the water-waves suggested to several physicists, toward the
close of the nineteenth century, the possibility of verifying the earth's
motion by experiments on the speed of light.

True, the speed of the earth in its orbit is only one ten-thousandth of
the speed of light, but methods were available of more than sufficient
precision to pick up an effect of this order of magnitude. It was, there-
fore, with the greatest surprise, not to say consternation, that the results
of all such experiments were found to be negative; that analogy, for
some unexplained reason, appeared to have broken down somewhere
between mechanics and optics; that while the speed of water-waves varied
as it should with the speed of the observer, the velocity of light seemed
completely unaffected by such motion.

Nor could any fault be found with method or technique. At least three
independent lines of experiment, two optical and one electrical, led to the
same negative conclusion.

This breakdown of analogy between mechanics and optics introduced
a sharp line of division into physical science. Now since the days of
Newton the general trend of scientific thought has been in the direction
of removing or effacing such sharp lines indicating differences in kind
and replacing them by differences in degree. In other words, scientific
thought is monistic, seeking one ultimate explanation for all phenomena.

Kepler, by his study of the planets, had discovered the three well-known
laws which their motion obeys. To him these laws were purely empirical,
separate and distinct results of observation. It remained for Newton to
show that these three laws were mathematical consequences of a single
broader law — that of gravitation. In this, Newton was a monistic
philosopher.

The whole of the scientific development of the nineteenth century was
monistic. Faraday and Oersted showed that electricity and magnetism
were closely allied. Joule, Mayer and others pointed out the equivalence
of heat and work. Maxwell correlated light with electricity and mag-
netism. By the close of the century physical phenomena of all kinds were

SPACE, TIME AND EINSTEIN 233

regarded as forming one vast, interrelated web, governed by some broad
and far-reaching law as yet unknown, but whose discovery was confi-
dently expected, perhaps in the near future. Gravitation alone obstinately
resisted all attempts to coordinate it with othtx phenomena.

The consequent reintroduction of a sharp line between mechanics and
optics was therefore most disturbing. It was to remove this difficulty
that Einstein found it necessary to alter our fundamental ideas regarding
space and time. It is obvious that a varying velocity can be made to appear
constant if our space and time units vary also in a proper manner, but
in introducing such changes we must be careful not to cover up the
changes in velocity readily observable in water-waves or sound waves.

The determination of such changes in length and time units is a purely
mathematical problem. The solution found by Einstein is what is known
as the Lorentz transformation, so named because it was first found (in
a simpler form) by Lorentz. Einstein arrived at a more general formula
and, in addition, was not aware of Lorentz's work at the time of writing
his own paper.

The evidence submitted so far for Einstein's theory is purely retrospec-
tive; the theory explains known facts and removes difficulties. But it must
be remembered that this is just what the theory was built to do. It is a
different matter when we apply it to facts unknown at the time the
theory was constructed, and the supreme test is the ability of a theory to
predict such new phenomena.

This crucial test had been successfully met by the theory of relativity.
In 1916 Einstein broadened his theory to include gravitation, which since
the days of Newton had successfully resisted all attempts to bring it into
line with other phenomena. From this extended theory Einstein predicted
two previously unsuspected phenomena, a bending of light rays passing
close by the sun and a shift of the Fraunhofer lines in the solar spectrum.
Both these predictions have now been experimentally verified.

Mathematically, Einstein's solution of our theoretical difficulties is
perfect. Even the paradox of the two clocks, each appearing slower than
the other, becomes a logical consequence of the Lorentz transformation.
Einstein's explanation is sufficient, and up to the present time no one has
been able to show that it is not necessary.

Einstein himself is under no delusion on this point. He is reported to
have said, "No amount of experimentation can ever prove me right; a
single experiment may at any time prove me wrong."

Early in the present year Einstein again broadened his theory to include
the phenomena of electricity and magnetism. This does not mean that
he has given an electromagnetic explanation of gravitation; many attempts

234 MATTER, ENERGY, PHYSICAL LAW

of this kind have been made, and all have failed in the same respect — to
recognize that there is no screen for gravitation. What Einstein has done
is something deeper and broader than that. He has succeeded in finding
a formula which may assume two special forms according as a constant
which it contains is or is not zero. In the latter case the formula gives
us Maxwell's equations for an electromagnetic field; in the former,
Einstein's equations for a gravitative field. . . .

Einstein's aim from the first has been to bring order, not confusion;
to exhibit all the laws of nature as special cases of one all-embracing
law. In his monism he is unimpeachably orthodox.

But there are other monistic philosophers besides scientific men. You
will recall Tennyson's vision of

One law, one element,

And one far-off, divine event

To which the whole creation moves.

1929

The Foundations of Chemical Industry

ROBERT E. ROSE

PRELUDE: THE JUGGLERS

AJL OF US HAVE SEEN THE JUGGLER WHO ENTERTAINS
by throwing one brightly colored ball after the other into the air,
catching each in turn and throwing it up again until he has quite a
number moving from hand to hand. The system which he keeps in motion
has an orderly structure. He changes it by selecting balls of different colors,
altering the course or the sequence of the balls, or by adding to or
diminishing the number with which he plays.

With this figure in mind let us use our imaginations. Before us we have
an assemblage of hundreds of thousands of jugglers varying in their
degree of accomplishment; some handle only one ball, others, more
proficient, keep several in motion, and there are still others of an as-
tounding dexterity who play with an hundred or more at once. The balls
they handle are of ninety different colors and sizes. The jugglers do not
keep still but move about at varying rates; those handling few and light
balls move more quickly than those handling many or heavier ones.
These dancers bump into each other and when they do so in certain
cases they exchange some of the balls which they are handling or one
juggler may take all of those handled by another, but in no case are the
balls allowed to drop.

THE VANISHING POINT

Now imagine the moving group to become smaller and smaller until
the jugglers cease to be visible to us, even when they dance under the
highest power microscope. If someone who had not seen them were to
come to you and say that he proposed undertaking the problem of finding
out how the balls were moving and what were the rules of the exchanges
made, and further that he proposed utilizing his knowledge to control
what each minute juggler was doing, you would tell him that his task was

235

236 MATTER, ENERGY, PHYSICAL LAW

hopeless. If the chemist had listened to such advice there would be
no chemical industry and you would lose so much that you would not be
living in the way you are.

The jugglers are the electromagnetic forces of matter, the balls are the
atoms, and each group in the hands of the juggler is a molecule of a
substance. In reality, of course, instead of each molecule being represented
by one unit we should multiply our jugglers by trillions and trillions.

THE MASTERY OF MOLECULES

The chemist, without even seeing them, has learned to handle these
least units of materials in such a way as to get the arrangements which
are more useful from those less useful. This power he has acquired as the
outcome of his life of research, his desire to understand, even though
understanding brought him no material gain, but mere knowledge.
Because of his patience and devotion he has built a number of industries;
all have this in common — they serve to rearrange atoms of molecules or
to collect molecules of one kind for the service of man.

THE GREAT QUEST

The study of the substances of the earth's crust, of the air over and of
the waters under earth, which has led us to our present knowledge of the
electron, atom, and molecule, has been more adventurous than many a
great journey made when the world was young and the frontier of the
unknown was not remote from the city walls. Into the unknown world
of things upon the "sea that ends not till the world's end" the man of
science ventured, and he came back laden with treasure greater than all
the gold and precious stones ever taken from the earth. He gave these to
others and he fared forth again without waving of flags, without the
benediction of holy church, with no more than the courage of him who
would win Nature, who had chosen a harder road than that of the great,
made famous because of subduing other men. He took no arms upon his
quest, scarcely enough food to keep body and soul together, but instead,
fire, glass, and that most astounding of all tools, the balance. As he pushed
farther and farther on his great venture and as more and more joined his
little band, he brought more and more back to those who did not under-
stand in the least what he was doing, until now the lives of all men
are made easier if not happier by these strange, most useful, and
most potent things of which he is the creator by reason of the under-
standing his journeys have given him — a power much greater than
any mere black magic.

THE FOUNDATIONS OF CHEMICAL INDUSTRY 237

This is the story of some of the strange treasure found by him in the
far lands that are about us— treasure found by learning the secret of
the jugglers' dance— the dance of the least little things out of which all
we know is fashioned.

SULFURIC ACID

The Great Discovery

In Sicily and other parts of the earth where there are volcanoes, lumps
of a yellow crumbly "stone" are found, called brimstone (a corruption of
brcnnisteinn or burning stone). This material was regarded as having
curative properties; if it was burned in a house the bad odors of the
sickroom of primitive times were suppressed. Also the alchemists found
that it took away the metallic character of most metals and they con-
sidered it very important in their search for the philosopher's stone, the
talisman that was to turn all things to gold. The alchemists found also
that sulfur, when burned over water, caused the water to become acid, and
one of them found further that if the burning took place in the presence
of saltpeter the acid which was produced was much stronger; indeed, if
concentrated it was highly corrosive. A useless find, it seemed, of interest
only to the alchemist who hoped to become rich beyond the dreams of
avarice, and immortal as the gods. But the chemist made this discovery of
more importance to the condition of the human race than that of Colum-
bus, because by it he gave man a kingdom different from any that could
have been his by merely discovering what already existed upon earth.
That is the wonder of the chemist's work; he finds that which is not upon
the earth until he discovers it; just as the artist creates so does the chemist.
If he did not, there would be no chemical industry to write about.

Experiment to Manufacture

Having investigated this acid, he found it a most valuable new tool
with which many new and interesting things could be made, and much
could be done that before had been impossible. It became necessary, then,
if all men were to profit as the chemist always wishes them to do by his
power, that sulfuric acid should be made easily and cheaply in large
quantities. The first attempt at commercial manufacture was in 1740;
before that each experimenter made what little he needed for himself.
The process, that mentioned above, was carried out in large glass bal-
loons. It was a costly method and tedious. Then in 1746 lead chambers
were substituted for the glass and the industry progressed rapidly.

238 MATTER, ENERGY, PHYSICAL LAW

The whole object of this most basic of all chemical industries can be
written in three simple little equations.

Sulfur Oxygen Sulfur Dioxide

S + O2 = SO2

Sulfur Dioxide Oxygen Sulfur Trioxide

502 + O2 = SO3
Sulfur Trioxide Water Sulfuric Acid

503 + H20 = H2S04

Of the three elements necessary, oxygen occurs uncombined in the
air of which it forms one-fifth by volume; it is also present combined with
other elements in very large quantities in water, sand, and generally
throughout the earth's crust, which is nearly half oxygen in a com-
bined condition.

The Raw Materials

The great storehouse of hydrogen on the earth is water, of which it
forms one-ninth, by weight. Sulfur is not so widely distributed in large
quantities but it is very prevalent, being present in all plants and animals
and also in such compounds as Epsom salts, gypsum, and Glauber's salt.
In the free condition, i.e., as sulfur itself, it is found in volcanic regions
and also where bacteria have produced it by decomposing the products of
plant decay. There is one other source of sulfur that is quite important,
a compound with iron which contains so much sulfur that it will burn.

The problem then was to take these substances and from them group
the elements in such order as to produce sulfuric acid.

Since sulfur burns readily, that is, unites with oxygen to form sulfur
dioxide, one might expect it to take up one more atom of oxygen from the
air and become sulfur trioxide. It does, but so slowly that the process
would never suffice for commercial production. But there is a way of
speeding up the reaction which depends on using another molecule as a
go-between, thus making the oxygen more active. The principle is that
of the relay. Suppose an out-fielder has to throw a ball a very long way.
The chances are that the ball will not be very true and that it may fall
short of reaching the base. If there is a fielder between, he can catch the
ball and get it to the base with much greater energy.

The chemist uses as a go-between a catalyst (in one process), oxides of
nitrogen. Molecules of this gas throw an oxygen atom directly and un-
failingly into any sulfur dioxide molecule they meet, then equally cer-
tainly they seize the next oxygen atom that bumps into them and are
ready for the next sulfur dioxide molecule. Since molecules in a gas

THE FOUNDATIONS OF CHEMICAL INDUSTRY 239

mixture bump into each other roughly five billion times a second, there
is a very good chance for the exchange to take place in the great lead
chambers of approximately a capacity of 150,000 cubic feet into which are
poured water molecules (steam), oxygen molecules (air), and sulfur
dioxide, to which are added small quantities of the essential oxides o£
nitrogen.

The Acid Rain

A corrosive, sour drizzle falls to the floor and this is chamber acid.
It is sold in a concentration of 70 to 80 per cent. The weak chamber acid
is good enough for a great many industrial purposes and is very cheap.
If it is to be concentrated this must be done in vessels of lead up to a
certain concentration and then in platinum or gold-lined stills if stronger
acid is needed. Naturally this is expensive and every effort was made to
find a method of making strong sulfuric acid without the necessity of
this intermediate step. Especially was this true when the dyestuffs
industry began to demand very large quantities of tremendously strong
sulfuric acid which was not only 100 per cent but also contained a con-
siderable amount of sulfur trioxide dissolved in it (fuming sulfuric acid).

The difficulty was overcome by using another catalyst (platinum) in
the place of the oxides of nitrogen. If sulfur dioxide and oxygen (air)
are passed over the metal the two gases unite to form sulfur trioxide much
more rapidly and in the absence of water. Since platinum is very expensive
and its action depends on the surface exposed, it is spread on asbestos
fibers and does not look at all like the shiny metal of the jeweler. This
method is known as the contact process and the product is sulfur tri-
oxide, which represents the highest possible concentration of sulfuric acid
and can be led into ordinary oil of vitriol (98 per cent sulfuric acid) and
then diluted with water and brought to 98 per cent acid or left as fuming
acid, depending on the requirements of the case. The perfection of this
process was the result of some very painstaking research because when it
was tried at first it was found that the platinum soon lost its virtue as a
catalyst, and it was also discovered that the reason for this was the
presence of arsenic in the sulfur dioxide. To get rid of every trace of
arsenic is the hardest part of the contact process.

Vitriol

Next time you visit a laboratory ask to be shown a bottle of concen-
trated sulfuric acid. You will see a colorless, oily liquid, much heavier
than water, as you will notice if you lift the bottle. A little on your skin

240 MATTER, ENERGY, PHYSICAL LAW

will raise white weals and then dissolve your body right away; paper is
charred by it as by fire. When it touches water there is a hissing.

Sulfuric Acid and Civilization

A dreadful oil, but its importance to industry is astonishing. If the art
of making it were to be lost tomorrow we should be without steel and
all other metals and products of the metallurgical industry; railroads,
airplanes, automobiles, telephones, radios, reenforced concrete, all would
go because the metals are taken from the earth by using dynamite made
with sulfuric acid; and for the same reason construction work of all
kinds, road and bridge building, canals, tunnels, and sanitary construction
work would cease.

We should have to find other ways to produce purified gasoline and
lubricating oil. The textile industry would be crippled. We should find
ourselves without accumulators, tin cans, galvanized iron, radio outfits,
white paper, quick-acting phosphate fertilizers, celluloid, artificial leather,
dyestuflfs, a great many medicines, and numberless other things into the
making of which this acid enters at some stage.

If at some future date, however, all of our sulfur and all of our sulfur
ores are burned up the chemist will yet find ways of making sulfuric acid.
Possibly he may tap the enormous deposits of gypsum which exist in all
parts of the earth. This has been done to some extent already but is not
a process which is cheap enough to compete with sulfuric acid made
from sulfur.

NITRIC ACTD

It is essential that all the heavy chemicals, that is, the most used acids,
alkalies, and salts, should be made so far as possible from readily available
cheap material. We use air, water, and abundant minerals on this account.
Nitric acid caused the chemical industry much concern until it was found
possible to make it from air, because until then its source was Chile
saltpeter, or sodium nitrate, a mineral occurring in a quantity only in the
arid Chilean highlands. However, this source of supply is still the most
important and the process used is one of great interest.

Having made oil of vitriol, the chemist found that he could produce
other acids, one of the most important of these being liberated from salt-
peter by the action of sulfuric acid. When nitric acid is made in this
fashion we find that the sulfuric acid is changed into sodium sulfate and
remains behind in the still. One might think from this that sulfuric acid
is stronger and on that account that it drives out nitric acid, but in fact

THE FOUNDATIONS OF CHEMICAL INDUSTRY 241

this preparation depends on a very simple principle, one of great
importance.

Another Dance

We may best illustrate it by returning to our former simile. Let us
assume a sodium nitrate juggler moving rather slowly. He is bumped
into by a sulfuric acid juggler moving at about the same rate. They
exchange some of the atoms with which they are playing and in conse-
quence one juggler holds sodium hydrogen sulfate while the other holds
nitric acid.

NaN03 + H2S04 -» NaHSO4 + HNO3

The nitric acid molecule does not slow down the juggler as much as
the sodium hydrogen sulfate and therefore this particular dancer moves
away quite fast. Suppose millions of these exchanges to be taking place;
then the nitric acid molecules will continue to dance away and will not
come back to exchange their atoms any more. If we keep them all in by
putting a lid on, then they are forced to go back and we get no more
than a sort of game of ball in which the hydrogen and sodium atoms are
passed back and forth. If, on the other hand, we open the lid and put a
fire under the pot, the nitric acid molecules move faster and sooner or
later all of them are driven out.

Nitric acid is now made from the air in more than one way so that
we are entirely independent of the beds of Chile saltpeter no matter what
might happen to them. Without nitric acid we could not make gun-
cotton, dynamite, TNT, picric acid, ammonium nitrate, and the other
explosives which are so enormously important to our civilization. In addi-
tion, we would lose all our brilliant dyes and most of our artificial silk,
from which it is easy to see that this substance is of great importance to
all of us.

SALT, THE JEWEL BOX

Soda

Among the treasures to which man fell heir as the most important
inhabitant of the earth was one of innumerable little cubes made of
sodium and chloride, crystals of salt. These he noticed whenever seawater
evaporated and he soon found, if he lived on a vegetable diet as he did in
some places, that the addition of these to his food made it much more
pleasant and savory. It fact, it is a necessity for the health of the human
body, Hunting peoples do not use it so much because they live almost

242 MATTER, ENERGY, PHYSICAL LAW

entirely on meat, which contains sufficient salt. Next it was found that
salt could be employed for preserving fish and meat, and thus man was
able to tide over the periods in which hunting was poor. For ages and
ages it was put to no other use. Nobody but a chemist would have thought
of doing anything with it. In order to understand the whole of what he
did and the part which salt plays in industry owing to the chemist's
activity we must go back a little.

Soap as a Hair Dye

Very early it was found that the ashes of a fire (and fires at that time
were always made of wood) were useful in removing grease from the
hands. They were the earliest form of soap and it is surprising how long
they remained the only thing used. Our records go to show that the
Romans were the first of the more civilized peoples to find out how to
make real soap, and they learned it from the Gauls, who used the ma-
terial which they made from wood ashes and goat's tallow for washing
their hair and beards because they believed that this gave them the
fiery red appearance which they thought was becoming. The Romans
saw the advantage of soap over wood ashes and a very considerable trade
in the making of various kinds of soaps arose, but the difficulty always
was with the production of the ashes because it takes quite a lot of ashes
to make even a small quantity of soap. The advantage of having some-
thing more abundant to take the place of the ashes was evident. But
the real stimulus which led to the discovery of soda ash came from a
different source.

Glass from Ashes and Sand

It was found that ashes heated with sand formed glass. It was also
found that the ashes of marine plants, or plants occurring on the seashore,
gave a much better glass than that which could be made from the ashes
of land plants. In consequence of this, as the art of glass making grew,
barilla, the ashes of a plant growing in the salt marshes of Spain, became
an increasingly important article of commerce and upon it depended the
great glass factories of France and Bohemia. Owing to the political
situation which arose at the end of the eighteenth century, France found
herself in danger of losing her supremacy in the art of making glass
because England cut off her supply of the Spanish ashes. For some reason
the French ruler at the time had vision enough to see that it might
be possible to make barilla artificially from some source within the
kingdom of France and he offered a prize to any one who would make
his country independent of Spain. We have seen that the chemist's busi-

THE FOUNDATIONS OF CHEMICAL INDUSTRY 243

ness is the transmutation of one kind of material into another, and
naturally it was the chemist who came forward with a solution of the
problem. Since this process is now supplanted by a more economical one,
we will merely outline it here.

Limestone to Washing Soda

Remember that it is essential to start from some abundant common
material. Le Blanc, the chemist who solved the problem, knew that the
Spanish ashes contained sodium carbonate, the formula of which we
write as Na2COs; that is, it is a combination of sodium, carbon, and
oxygen. There are a great many carbonates in nature and among these
is that of calcium which we know as chalk, limestone, or marble, depend-
ing on the way in which it crystallizes. In this we have a substance of the
formula CaCOa. Suppose, then, we write the two compounds side by side:
Na2COa, CaCOa. Evidently the only difference is that in one we have two
atoms of sodium (Na2) in place of one of calcium (Ca) in the other.
Salt contains sodium and is very common. If, then, we can get the sodium
radical from the sodium chloride and the carbonate radical from the
limestone and join the two pieces we will get sodium carbonate, which
is what we want. What Le Blanc did was to treat sodium chloride with
sulfuric acid. This gave him sodium sulphate and hydrochloric acid. Then
he heated the sodium sulfate with coke or charcoal and limestone, after
which he extracted the mass with water and found that he had sodium
carbonate in solution.

The steps do not sound difficult but it was really a great feat to
make them commercially possible. In the first stage when sulfuric acid
acted on the salt, hydrochloric acid was given off and this was a great
nuisance. The amount of it produced exceeded any use that could be
found for it and it was poured away; being highly acid it undermined
the houses in the neighborhood and caused a great deal of trouble. Later,
it became the most valuable product of the process because it was con-
verted into bleaching powder by a method that we will take up subse-
quently.

Industry a Result of Chemical Discovery

It is interesting to learn that this process which France invented in her
extremity became one of the largest industrial developments in England.
It caused the flourishing there of the sulfuric acid industry because this
acid was necessary for the process and, as we have seen, sulfuric acid is
tremendously valuable in a great variety of directions. It also made
possible the development of an enormous textile industry because the

244 MATTER, ENERGY, PHYSICAL LAW

making of cloth needs soap and bleach, both of which were first supplied
in abundance as a consequence of Le Blanc's discovery.

To return to the story of the chemist's transformations of salt, the
present process for the conversion of this compound into sodium car-
bonate is by the action of ammonia and carbon dioxide upon a saturated
solution of it, the carbon dioxide being obtained from limestone. When
these three substances are brought together a change takes place which
can best be described by the following equation:

Carbon Ammonium

Ammonia

Water

Dioxide

Bicarbonate

NH3 +

H20 +

CO2

= NH4 HCO3

Ammonium

Sodium

Ammonium

Salt

Bicarbonate

Bicarbonate

Chloride

NaCl +

NH4 HCO3 =

NaHC03

+ NH4 Cl

The change that takes place depends on the fact that sodium bicarbonate
is comparatively insoluble and separates out. It is collected and then
heated, the heat causing it to turn into sodium carbonate, carbon dioxide,
and water.

2 NaHCO3 = Na2CO3 + CO2 + H2O

In this process the essential thing is to keep the ammonia in the system,
because it is used over and over again and, if it escapes, an expense arises
out of all proportion to the value of the carbonate which must be sold
at a price of about two cents per pound. The ammonia goes out of the
reaction, as indicated in the equation, in the form of ammonium chloride
and this is returned to the process by allowing quicklime, made by heating
limestone in kilns, to decompose the chloride. The other part of the
limestone (the carbon dioxide) is also used in the process, as shown in the
first equation. We start then with salt, water, and limestone, and we finish
with calcium chloride and sodium carbonate.

Caustic Soda

This is not all that the chemist was able to do with salt. In soap making
much better results are obtained if, instead of using wood ashes which
give us nothing but an impure soft potash soap, we use sodium hydroxide
or caustic soda. Now, caustic soda is something which does not occur in
nature because it always combines with the carbon dioxide of the air or
with some acid material and disappears. The old method of making it
was to take the soda of the Le Blanc process and to treat it with slaked
lime. In this way we can make about a 14 per cent solution of caustic
soda which is then evaporated if it is required in a more concentrated

THE FOUNDATIONS OF CHEMICAL INDUSTRY 245

form. This method of making caustic soda was sufficiently economical to
give us all that we needed at very reasonable prices, but eventually a
better method was discovered.

Caustic soda is NaOH, that is to say, it is water (HbO) in which one
of the hydrogens has been replaced by sodium. If in any way we could
make this reaction take place, NaClH- HOH = NaOH + HCl, we would
get directly two products which we want. Unfortunately, it is impossible
to get salt to exchange atoms in this way with water. However, a study
of salt solutions showed that the atoms of sodium and chlorine were
actually separated when in solution and that they also acquired a property
which would allow of their segregation. They became electrically charged
and it is always possible to attract an electrically charged body by using
a charged body of opposite sign. If, then, we put the positive and the
negative pole of a battery or another source of electricity in a solution
of salt the chlorine will wander away to the positive and the sodium
will wander to the negative pole.

Electrons

What takes place can best be described by a rough analogy. Suppose
two automobiles of different makes are running side by side, keeping
together because of the friendship which exists between the two parties.
Now suppose these two machines have an accident in which, by a freak,
one wheel is torn off one car and added to the other. Assume that the
occupants of the car are not damaged and that the cars can still run; also
that the fifth wheel is a distinct nuisance. If there were two garages at
considerable distances, one of which specialized in taking off extra wheels
and the other did nothing but put on missing wheels, and the accident
were a common one involving thousands of machines, then it would be
natural for the cars to move in opposite directions to these two garages
and if we assume that all the wheels are interchangeable, then there
might be a traffic between the garages, by another road perhaps, the
wheels being sent from one to the other.

This very rough picture is intended to describe the fact that when the
sodium and chlorine atoms of salt are separated by water the electrons of
which they are composed are distributed in such a way that there is an
extra one in the chlorine which (an electron being negative) makes the
chlorine particle negative, while the sodium lacks one electron and there-
fore becomes positive since it was neutral before. The result, then, of
this electrolysis or use of the electric current in separating the charged
atoms of sodium chloride (the ions as they are called) is that sodium and
chlorine are given off at the two poles. Now, chlorine is not very soluble

246 MATTER, ENERGY, PHYSICAL LAW

in water and can be collected as a gas. The sodium, on the other hand,
as each little particle is liberated, reacts with the water about it to give
hydrogen and sodium hydroxide. Therefore, we have accomplished what
we set out to do, only instead of getting sodium hydroxide and hydrogen
chloride we get sodium hydroxide, chlorine, and hydrogen.

Electricity

The success of this method is due to discoveries in another field of
science. Only when Michael Faraday's researches on the nature of the
electric current made available another source of energy different from
heat, was it possible for the chemist to carry out what has just been
described; at first only in a very small way but, as the production of
electricity became more and more economical, ever on a larger scale until
now the industry is a most important one.

Chlorine

So far we have directed our attention almost entirely to the sodium
atom of salt; the other part of the molecule, the chlorine, is also extremely
valuable to us. It used to be set free by oxidizing hydrochloric acid of the
Le Blanc process with manganese dioxide. Now, as we have just seen, we
get it directly from a solution of salt by electrolysis.

Uses of Caustic Soda

The two servants which the chemist has conjured out of salt by using
electricity are extremely valuable, though if they are not handled rightly
they are equally as dangerous as they are useful when put to work. Caustic
soda is a white, waxy-looking solid which is extremely soluble in water
and attracts moisture from the air. It is highly corrosive, destroying the
skin and attacking a great many substances. When it is allowed to act on
cellulose in the form of cotton the fiber undergoes a change which results
in its acquiring greater luster so that the process of mercerizing, as it is
called, is valuable industrially. The manufacture of artificial silk made by
the viscose method depends on the fact that caustic soda forms a com-
pound with cellulose. Practically all the soap manufactured at the present
time is produced by the action of caustic soda on fat. The by-product of
this industry is glycerol which is used in making dynamite. In fact, soda
is just as important among alkalies as sulfuric acid is among acids.

Uses of Chlorine

Chlorine, the partner of sodium, is a frightfully destructive material. It
attacks organic substances of all kinds, destroying them completely, and
it also attacks all metals, even platinum and gold, though fortunately, if

THE FOUNDATIONS OF CHEMICAL INDUSTRY 247

it is quite dry, it does not react with iron, and on that account it can be
stored under pressure in iron cylinders. Although it is such a deadly gas
if allowed to run wild, yet it is extremely useful and its discovery has been
very greatly to the advantage of the human race. First of all, it is employed
in the manufacture of bleaching powder, a product which enables the
cotton industry to work far more intensively than it otherwise could.
Formerly cotton was bleached by laying it on the grass, but that is much
too slow for our present mode of life. In fact, we have no room for it
because it has been calculated that the cotton output of Manchester,
England, would require the whole county as a bleaching field and this is
obviously impossible. Then came the discovery that this same compound
could be used in purifying our water supplies of dangerous disease-breed-
ing bacteria and this has reduced the typhoid death rate from that of a
very dangerous epidemic disease to a negligible figure. Now, whenever
the water supply of a city is questionable, chlorine is pumped right into
the mains or else a solution made from bleaching powder is used. Twenty
parts of bleaching powder per million is sufficient to kill 90 to 95 per
cent of all the bacteria in the water. For medical use, a solution of hypo-
chlorous acid, which is the active principle of bleaching powder, has been
developed into a marvelous treatment for deep-seated wounds, and
recoveries which formerly would have been out of the question are now
possible. Chlorine is also used in very large amounts in making organic
chemicals which the public enjoys as dyestuffs or sometimes does not
enjoy as pharmaceuticals or medicines.

All in all, the products obtained from the little salt cube are of extreme
necessity and importance to every one of us and their utilization shows
what can be done when men of genius devote themselves to the acquisi-
tion of real knowledge and then translate their discoveries into commercial
enterprises for the benefit of humanity.

CHEMISTRY AND UNDERSTANDING

The brief story for which we have space indicates but very dimly the
real interest and fascination the chemist has in handling matter. His
knowledge has increased to such a point that he can build you a molecule
almost to order to meet any specifications. To be without any knowledge
of chemistry is to go through life ignorant of some of the most interesting
aspects of one's surroundings; and yet the acquisition of some knowledge
of this subject is by no means hard. There are any number of books which
tell the story in simple language if you do not wish to study the science
intensively. On the other hand, all that you need is a real interest and a
willingness to think as you read.

The Chemical Revolution

WALDEMAR KAEMPFFERT

From Science Today and Tomorrow

FROM THE ADVERTISEMENT OF A NEW YORK DEPART-
MENT STORE:

Grandma got by with a new bonnet and a smear of talc across her pretty
little nose — but times have changed. To make it easier for modern beauties
we have assembled the Personal Spectrum Kit with all related cosmetics to
suit your individual coloring.

From an article by Edsd Ford, exploiter of soy beans and builder of
motor cars:

Our engineers tell us that soy-bean oil and meal are adaptable to by far
the greater part of the many branches of the whole new plastic industry,
and that shortly we are to see radio and other small cabinets, table tops,
flooring tile in a thousand different color combinations, brackets and sup-
ports of a hundred varieties, spools and shuttles for the textile trades,
buttons and many other things of everyday use all coming from the soy-
bean fields.

From an address by the director of an industrial research laboratory:

In 1913 the most carefully made automobile of the day had a body to
which twenty-one coats of paint and varnish were applied. By 1920,
through scientific management, it was possible to do a body-painting job
in about eleven days. In 1923 came the first nitrocellulose lacquers. They
cut the time to two days. Now a whole body is made out of metal and
coated with any color in a day.

From a German scientific magazine:

Over twenty-five years ago the German chemist Todtenhaupt patented
a process to convert the casein of milk into artificial wool. Under the
economic stress of the Ethiopian war the Italians developed the process and
by October 1936 will produce several hundred thousand pounds annually
of artificial wool. No one pretends that it is indistinguishable from natural

248

THE CHEMICAL REVOLUTION 249

wool. It is still imperfect, but no more imperfect than were the first fibers
of artificial silk. It meets men's needs — all that can be reasonably de-
manded.

Cosmetics, soy-bean products, lacquers, casein "wool" — all are "syn-
thetic," as the term is somewhat loosely used nowadays. There are thou-
sands more like them, transformations of such familiar raw material as
coal, petroleum, wood, slaughterhouse refuse. Indeed, every article that we
touch is a chemical product of some kind, and many a one has no counter-
part in nature.

Despite a million chemical compounds known to technologists, despite
the manifest artificiality of clothes, houses, vehicles, food — all the result of
chemical progress — we have made but a beginning in the creation of a new
environment. If the test of a culture based on science is the degree of its
departure from nature — woven cloth instead of skins, gas in the kitchen
instead of wood, electric lights instead of naked flames, rayon instead of
silk — we are still chemical semi-barbarians.

It is beside the mark to argue that a culture consists of something more
than plastic compounds that take the place of wood and metal. Our society
is what it is just because the engineer and the chemist have struggled with
nature, torn apart her coal, her trees, her beauty, discovered how they were
created, and then proceeded to make new combinations of their own. The
lilies of the field and the honey of the bee are not in themselves sufficient.
On every hand there is synthesis and creation — scents, fabrics, drugs, plas-
tics, metals like aluminum, sodium, and a few thousand alloys that nature
forgot to make when the earth was a cooling but still glowing ball, dyes,
unmatched by any gleam in the iridescent feathers of a peacock's tail, high
explosives, lung-corroding gases, talking-machine records made of carbolic
acid derivatives or artificial resins.

More than the substitution of a synthetic for a natural product is in-
volved. Buttons that look like ivory or bone but are neither, fibers that
mimic silk but are better, automobile upholstery that passes for leather
but is a form of guncotton, photographic films that bring the same screen
plays to tens of millions simultaneously for as little as 25 cents — these are
the outward evidences of a breaking down of social distinctions, of a pro-
found change in life. Gunpowder made all men the same height, said
Carlyle in a fine but unwitting comment on chemistry. The leveling is not
yet ended.

New industries came with the rise of chemistry, and with them new
opportunities for the many. There is a closer relation between democracy
and the laboratory than the historians recognize. The environment has

250 MATTER, ENERGY, PHYSICAL LAW

been chemically changed, and with that change has come a new vision of
the social future. Is the world ready?

Already a beginning has been made in three-dimensional chemistry. The
potentialities are infinite, breath-taking. Suppose you want something as
transparent as glass but as strong as metal. A three-dimensional chemistry
may achieve it. There is even the possibility that active compounds may
be devised — active in the sense that they would shrink from blows or
electric shocks just as if they were alive.

Much so-called synthesis is merely a transformation of some natural
product. Yet it is an evidence of social and scientific progress. It was a tre-
mendous step from killing an animal and wearing its skin for protection
to weaving a fiber on a deliberately invented loom, and thus making a soft
pliable fabric. But the fibers were nature's after all.

Indians once froze on ledges of coal. Mankind leaped ahead when
inventors showed how coal could be used to raise steam and drive an
engine. But the new conception of coal is chemical. It is a conception of
cosmetics, alcohol, drugs, strange artificial sugars, a million useful com-
pounds. So with wood. It is no longer a material out of which tables and
chairs and houses are built, but cellulose, which can be reconstructed to
assume the form of shimmering, silk-like filaments, cattle fodder, explo-
sives. . . .

Perhaps the most imminent of all the changes that the chemical revolu-
tion will bring about will affect the materials of engineering. This age of
power also is the age of steel. Age of rust would be a better designation.
If it were not for our paints and protective coatings nothing would be left
of this machine civilization a hundred years hence. No less an authority
than Sir Robert Hadfield has estimated that 29,000,000 tons of steel rust
away every year at a cost to mankind of $1,400,000,000. And this is not all.
To produce every pound of this metal, lost by conversion into oxide, four
pounds of coal had to be burned. The chemical revolution has already
ushered in the age of alloys, many of then non-corrosive. There are 2000
of them, and we have nardly begun to create all that the world needs.
Parts of gasoline engines are now made of aluminum alloys. All-metal
airplanes have for years been made of duraluminum— a strong, tough,
artificial metal. Aluminum alloys can be made as strong as steel. Very
rapidly they are making their way in industry.

What a tremendous amount of energy is wasted in hauling, lifting, and
spinning unnecessarily heavy masses of metal! It costs now 5 cents a pound
a year to move the dead weight of a street car. Think of the solid steel
trains hauled by solid steel locomotives, of automobiles made largely of
steel, of cranes that must be made of tremendous size and power to Hit

THE CHEMICAL REVOLUTION 251

gigantic masses of steel machinery! Tradition has obsessed us with the
notion that weight and strength are synonymous. Gradually the metal-
lurgist is breaking down this old conservatism.

Ten thousand years ago, indeed until very recently, the metallurgist was
a random smelter and mixer of metals. Bronze was one of his magnificent
accidental discoveries. But how different today! With X-rays he peers right
into the heart of a crystal — for nearly everything in the crust of the earth
is crystalline — and sees how the atoms are placed. He juggles temperatures
— relates them to such properties as toughness, magnetism, lightness. He
makes a mixture of aluminium, nickel, and copper. The result is a
magnet that can lift a hundred times its own weight or an alloy so light
that stratosphere balloon gondolas are made of it.

Already he has reached the stage where he can synthesize a metal for a
special purpose. Suppose he were to design and build an alloy with five
times the tensile limit of any we now have — not a wild impossibility. When
he succeeds, "the art of transportation on land and sea will be revolu-
tionized and, unfortunately, the methods of warfare," thinks Dr. Vannevar
Bush of the Massachusetts Institute of Technology.

Many of these alloys still to be discovered will be used in the home.
Wood as a structural material is already doomed. Two centuries hence an
ordinary white-pine kitchen chair of today will be treasured as an almost
priceless antique. Quarried stone will be used only for buildings near the
quarry. For the most part our houses will be cages of rustless alloy steel,
around which cement or some other artificial plastic material will be
poured.

Furniture will be made of a beautiful synthetic plastic material, a com-
bination of carbolic acid and formaldehyde discovered and first applied
industrially by a Belgian chemist, Dr. L. H. Baekeland, which is destined
to become so cheap that it will compete with wood. The panes of the
windows through which sunlight streams and the glassware that glitters
on the carbolic acid-formaldehyde sideboard will be made of a scratch-
proof synthetic product of organic chemistry which will be transparent,
insoluble in water, and unbreakable.

Draperies, rugs, bed and table "linen" by the year 2000 will be tissues
of synthetic fibers. Washing will be obsolete. Bedsheets, tablecloths, and
napkins will be thrown away after use. Draperies and rugs will not be
cleaned, for as soon as they show signs of dirt or wear new ones will take
their places. The household of the chemical future will probably spend no
more in a year for its fabrics than it does now for mere laundering. Hence
housework will be reduced to a pleasant minimum involving scarcely more
than the dusting of synthetic furniture and the mopping of synthetic floors.

252 MATTER, ENERGY, PHYSICAL LAW

Synthetic, too, will be the apparel of those who will live this easy life,
Cotton, silk, wool, and such fibers as linen will still be spun, but only the
very rich or the very snobbish will buy the fabrics into which they are
woven. Such material will be as unnecessary as are the expensive furs in
which fashionable men and women still clothe themselves — mere survivals
of a picturesque time when animals had to be skinned or clipped to make
a suit of clothes. Already the silkworm is doomed as an adjunct of indus-
try. Time was when only the worm knew how to change the woody
tissues, or cellulose, of a tree into glossy threads. Now the chemist converts
the tree into rayon and even makes silk, or something very like it, out of
coal, limestone, and nitrogen.

Synthetic wool is a commercial reality. The achievement was inevitable.
Perhaps within ten years, certainly within twenty, a man will buy a ready-
made suit of synthetic wool as warm as any now made from natural wool,
and free from shoddy, and $10 will be a high price to pay for it. Even the
most knowing sheep would be deceived by the yarn. There will be the
same "feel," the same fluffiness and waviness.

This $10 suit is almost attainable now. In the more distant future syn-
thetic fibers still to be evolved will completely revolutionize tailoring. The
cheapest suit of clothes is now stitched. What if machines do most of the
sewing and if buttonholes are mechanically formed and finished ? The cost
is high. Suppose we assign to the chemist and the efficiency engineer this
problem of keeping the body warm and the person presentable. The first
step is to abandon the old tradition of durability. Why must even the
cheapest suit last at least a year? Is not the standard merely a heritage from
a time when money was scarce and when a suit of clothes simply had to
endure?

The synthetic chemist proceeds to create new fibers. Cheapness is his
goal. His threads may be lacking in tensile strength and therefore in
durability. But the fabric into which they are woven is not intended to last
a year. Something much cheaper than artificial silk or wool is produced.
In fact, it is so cheap that a suit can be made for a dollar — a suit that will
be as ephemeral as a butterfly and will be thrown into the ash barrel in
two weeks. . . .

"* The synthetically clad man of the future will surely nourish himself on
synthetic food. Ultimately even the soluble dish will be regarded as an
interesting heirloom of a still fairly savage past when man chewed vege-
tation which had been boiled or baked, and actually killed and roasted
animals for the sake of their proteins. But the year 2000 seems much too
early a date for the achievement of synthetic nutriment, considering the
staggering difficulties that the chemist must overcome. . . .

*939

Jets Power Future Flying

WATSON DAVIS

HERE'S POWER IN ROARING FLAMES-WHETHER IN
-1L a windswept forest fire, your oil burner, or a jet plane of the future.

There's simplicity in a stream of speedy gas pushing an airplane for-
ward.

Jets with their simple power are revolutionizing travel through the air
— for peaceful transport or for atomic war if we fail in our attempt to get
along with the other peoples of the world.

Applying jet propulsion to our airplanes is the high priority task for
our research laboratories today. Already the P-8os, with turbine-jet engines,
have made obsolete the best conventional fighter planes with the best in-
ternal combustion engines. Jet bombers are being flown experimentally.
Jet transport planes are on the drawing boards.

The reciprocating, spark-fired internal combustion engine feeding on
gasoline (look under the hood of your automobile to see one) has a rival
that may drive it out of the air.

FOUR TYPES OF JETS

There are four different types of jet-propulsion units:

The turbo-jet and turbo-propeller-jet engines, which operate through
the principle of the gas turbine.

The pulse-jet, used by the Germans as the propulsion unit of the V-i
"buzz" bomb.

The ram-jet, currently undergoing rapid development for use on guided
missiles or other highspeed transportation.

The rocket, most highly developed in the German V-2 weapon.

Only the turbo-jet and turbo-prop-jet engines rely upon gas-turbine-
driven compressors to compress the intake air. The pulse-jet and the ram-
jet use oxygen of the air for burning their fuel, but compress the air by
their speed. The rocket supplies its own oxygen and thus can go outside
the atmosphere.

253

254 MATTER, ENERGY, PHYSICAL LAW

The principle of the combustion gas turbine is not new, but it makes
possible the development of turbo-jet and turbo-prop-jet engines for air-
craft. The future of marine and railroad locomotive propulsion will feel
its impact. History is full of attempts to develop a satisfactory gas turbine.
Early experimenters were unsuccessful. They were handicapped both by
lack of knowledge which would permit design of efficient compressors
and turbines, and by lack of the proper materials of construction.

WAR SPURRED RESEARCH

The wartime need for greater and greater speed in aircraft prompted
intensive research that before and during the war increased our knowledge
of aerodynamics. Metals were devised that would stand up for extremely
high temperatures. This made possible the development of the gas turbine,
in the form of the turbo-jet engine, for aircraft. This new type of engine
is one of the outstanding developments since the Wrights flew the first
heavier-than-air machines.

The design of the combustion gas turbine is simple. There is only one
major moving part, a rotating shaft on which is mounted an air compressor
and a turbine rotor. The compressor supplies air to the combustion cham-
bers where fuel is burned continuously to increase the energy content
of the compressed air by heating it. The resulting hot gases are then ex-
panded through a turbine. The turbine rotor and shaft revolve. In the case
of the turbo-jet engine, only sufficient energy is recovered by the turbine
to drive the compressor, and the hot gases leaving the turbine are exhausted
through nozzles to form the jet. The reaction to the jet propels the air-
craft as a result of the increase in momentum of the air stream due to its
rise in temperature and volume as it passes through the unit.

In the prop-jet engine, the greater part of the energy available in the
hot gases from the combustion chamber is recovered by the turbine. The
power thus available, over and above that required to drive the compressor
is utilized to drive an air screw propeller, in the case of high-speed aircraft.

Great amounts of fuel and air consumed by the gas-turbine engine in de-
veloping its great power are astounding. Philetus H. Holt, a research direc-
tor of the Standard Oil Development Co., has figured that a turbo-jet
engine developing 4,000 pounds thrust, equivalent to 4,000 horsepower at
375 miles per hour, will require more than 4,000,000 cubic feet of air in an
hour. At this rate, all the air in a typical six-room house would be exhausted
in about nine seconds. Approximately 20 barrels of fuel are burned each
hour — enough fuel, if it were gasoline, to drive an automobile 12,000 miles
at a speed of 60 miles per hour, or, if heating oil, enough to heat a typical
six-room house for two-thirds of a heating season.

JETS POWER FUTURE FLYING 255

Heat is released in the combustion chambers of the turbo-jet engine at
the rate of about 20,000,000 Btu. per hour per cubic foot of combustion
zone, which may be compared with a rate of one to two million Btu. per
hour per cubic foot in the case of industrial furnaces. This great develop-
ment of power is accomplished with a freedom from vibration unknown
in reciprocating engines.

HIGH-SPEED ENGINE

Where fuel economy is of secondary importance, the turbo-jet engine
far surpasses the conventional reciprocating engine when high speed at
present altitudes is necessary, as is the case in fighters, interceptors, and fast
attack bombers. When pressurized cabins are used combined with turbo-
jet power at very high altitude, fast, long-range commercial transports will
be attractive to airlines. At altitudes of 40,000 feet or higher the turbo-jet
unit is much more economical of fuel than at low altitudes.

Long flights of 3,000 miles, which presently take 12 to 14 hours, will be
made in six to seven hours. Equipment and pilots will do double jobs; pas-
sengers will get there faster.

The turbo-propeller-jet power plant has the possibility of competing
directly with the conventional reciprocating engine at present-day speeds,
since improvements in design should soon give fuel economy and operating
life equivalent to those of the reciprocating engine.

How soon will your airlines ticket give you such flight ? Some estimate
they will come in three years, others in five years and others still 10 years
or longer. The rapidity of their introduction, say the engineers, will be in
direct proportion to the amount and calibre of the effort expended in re-
search and development.

Turbo-jets will do their job at double the speeds of present airlines, but
aviation will turn to the ram-jet to surpass the speed of sound.

Speeds twice the speed of sound, some 1,400 miles per hour, have been
achieved for short flights by the "flying stovepipe."

Jap Kamikaze "suicide" planes sparked the post-haste development of
the ram-jet to power the Navy's "Bumblebee" anti-aircraft weapon that
would have been shooting them down if the war had lasted.

The ram-jet idea is not new, although, like other modern jet engines, it
is 20th century in its conception. Rene Lorin, a Frenchman, proposed in
1908 the use of the internal combustion engine exhaust for jet propulsion,
and in his scheme the engine did not produce power in any other way.
Five years later he described a jet engine where the air was compressed
solely by the velocity, or ram, effect of the entering air. This is the ram-jet.

The nickname of the ram-jet, "flying stove-pipe," describes what it looks

256 MATTER, ENERGY, PHYSICAL LAW

like. It is a cylindrical duct, with a varying diameter. The air enters through
a tapered nosepiece and it comes in at a speed above that of sound. The
ram-jet is only efficient when it goes through the air at speeds higher than
the speed of sound, which is about 700 miles per hour. In the military
version of the ram-jet, it is launched and brought up to speed by rockets
which soon burn themselves out and give way to the ram-jet itself.

Air entering the tube when the ram-jet is in flight is slowed down to be-
low the speed of sound. The air mixes with the fuel. The very simple de-
vice for doing this is at present one of the secrets in the ram-jet, as applied
as an anti-aircraft weapon. The diflfuser in the air duct stabilizes the
flame and the combustion of the gases increases very rapidly through the
duct. Just to the rear of the ram-jet the gases attain a speed of up to 2,000
miles per hour.

When supersonic transportation of mail, express and ultimately pas-
sengers is contemplated, the ram-jet offers a motor of great promise. The
present military development of this device is by commercial and industrial
agencies, under sponsorship of the Bureau of Ordnance of the Navy, with
the coordination of the Applied Physics Laboratory of the Johns Hopkins
University. This development may influence peacetime transportation of
the future world.

In the future, liquid fuels that are produced from petroleum will be made
to fit the requirements of jet engines. Particular fuel requirements for the
turbo-jet engine may even bring kerosene and other distillates heavier
than gasoline back into prominence.

During the war some of the jet planes were designed to burn kerosene
while other jet devices operated on hundred octane gasoline. Such high oc-
tane gasoline was not actually necessary but due to the fact that much of
the aviation fuel in the war areas was high octane, it was used to simplify
the problem of supply.

If jet planes were used in another war emergency, a fifth of the U. S.
petroleum refining capacity would be used for making jet fuels, Robert
P. Russell, president of the Standard Oil Development Co., estimated re-
cently. Designing of fuel that can be used in a variety of jet motors is as
important as designing jet motors themselves. Military specifications are
now being considered that will cause more of the fractions of petroleum
to be used in making jet fuel. This may prove to be one of the most im-
portant decisions affecting flying power for the future.

'947

Science in War and After

GEORGE RUSSELL HARRISON

From Atoms in Action

HHYPICAL OF THE TREND TOWARD REAL BATTLESHIPS
JL of the air is the Douglas ¥-19 bomber designed for the U. S. Army,
which made its first flight early in 1941. The yoton weight of this great
plane, twice as heavy as the famous Atlantic Clipper ships, is borne by
wings stretching 210 feet from side to side. With 11,000 gallons of gasoline
in its tanks to feed the four thirsty engines which release 2000 horsepower
each, this giant plane can carry 28 tons of bombs to a point 3000 miles
away, and return without re-fueling.

Though the trend will probably be toward even larger battleships of
the air, there is a limit to the weight of airplanes which can alight on
land. When the yo-ton bomber is on the ground its entire weight must
be supported on its wheels, and these are large and unwieldy in the
extreme. In fact, the only accident to the first of these great bombers
occurred when one of its wheels sank through a macadam pavement.
Pontoons rather than wheels will avoid this problem, and it seems likely
that the giant flying battleships of the future, if such there must be, will
rest on water when not in the air.

The tremendous destruction produced in Europe during the present
war by falling bombs is likely to lead one to think that the bomber has
everything his own way. This is becoming increasingly less true as defen-
sive measures are perfected. Entirely apart from this, the bomber who is
trying to destroy an important target is faced with a difficult problem at
best. Airplanes do not stand still in the air, or even travel in straight lines
when anti-aircraft shells are bursting around them, and to hit a target
five miles below from a platform moving erratically through the air at
400 miles an hour requires more than mere skill. It requires the assistance
of cleverly designed scientific apparatus — hence the great secrecy regard-
ing bomb-sights.

A bomb dropped from a plane strikes the ground far ahead of the point
directly under the position of the plane when the bomb was dropped.

257

258 MATTER, ENERGY, PHYSICAL LAW

Since the bomb when released is moving forward with the plane, usually
as fast as a revolver bullet, it falls to earth in a broad parabola. During the
twenty or more seconds which elapse while it is falling, it may travel
more than two miles forward. In addition, cross-winds at various levels
can in twenty seconds blow the bomb far to one side or the other. Various
bomb-sights have been developed which enable the pilot quickly and
automatically to allow for these effects. These are complicated combina-
tions of telescope, speed indicator, and computing machine whose details
are kept rigorously secret by the various powers.

During the first few months of the aerial bombardment of Britain in
1940 the German bombers seemed invincible, but gradually the funda-
mental truth, that for every new offense there is a satisfactory defensive
answer, has been borne out. First came the defeat of the day bomber by
the pursuit plane, and when losses during each daylight raid rose to 10
per cent, the Germans were forced to restrict bombing operations to the
hours of darkness, when pursuit planes could not find the bombers.

Several months passed during which night bombing raids were the
most pressing problem facing the British, but gradually hints began to
appear which indicated that a solution of the night-bomber problem was
imminent. At the end of 1940 the Air Chief Marshal announced that a
method for frustrating night bombers had been found, and in June of
1941, the basis of the method was made public. It was the radio-locator,
and this, widely publicized as Britain's secret defense weapon, gives an
excellent example of the use of science in defensive warfare. As far as an
enemy bomber is concerned the device is used to turn night into day. If
no light waves are available to see with, says the scientist, look around
for some other type of waves.

Actually nature perfected a similar method of detecting night fliers long
before the airplane was dreamed of. For hundreds of years bats have
been able to fly about in pitch-black caves without colliding with each
other or with obstacles in their paths. Scientists have stretched numerous
criss-cross wires in a room, and then darkened the room completely before
bats were brought into it, yet when the bats were released they flew
blithely about without once striking against a wire.

Careful tests showed that the bats were indeed flying blind, for when
adhesive tape was placed over both eyes a bat could avoid the wires quite
as well as with its eyes uncovered. Though the proverbial bat may be
blind, it can steer at high speed quite as well as any sharp-eyed lynx.

When adhesive tape was placed over the ears of the bats, however, the

SCIENCE IN WAR AND AFTER 259

results were very different — the uncanny power disappeared completely.
Similarly were they handicapped if the power of hearing was restored,
but their mouths were taped shut.

Scientists found that the bats were constantly broadcasting high-pitched
squeaks during flight, sounds so shrill that only occasionally could an un-
usually low one be heard by human ears. These sounds were quite audible
to the ears of the bat, and could of course be detected by special micro-
phones. When several bats were set flying around a dark room in which
only the flutter of skinny wings was audible to the crouching scientists,
the microphone detectors showed the air to be filled with a shrill clamor
of very short wavelength — a super-sound related to ordinary tones as
ultra-violet light is related to visible light. The human ear cannot hear
waves vibrating faster than 20,000 times a second, but the bat language
used for aerial navigation is found to be loudest at 50,000 vibrations a
second.

As a blind man walking along a sidewalk keeps tapping with his cane
to produce sounds which will be reflected from walls and other obstacles,
so the bat keeps broadcasting his shrill cries and these, reflected from other
bats, walls, or even wires, come back to his sensitive ears and warn him
of danger ahead.

Though these super-sound waves will do very well for the navigation
of bats, or even of boats, they would be of little help in steering airplanes
in the dark, for these waves move no faster than ordinary sound waves,
and we have already seen that a fast airplane flies at two-thirds of this
speed.

Far more effective for this purpose, and capable of being used in the
same way that bats use super-sound, are radio waves. These travel nearly
a million times as fast as sound waves, and since airplanes fly only about
ten times as fast as bats, this gives ample margin, providing science can
furnish a means of responding to the reflected wave which is about
100,000 times as fast as the response mechanism of the bat. This rapid
response mechanism British scientists have been able to develop.

To detect something with waves it is necessary that the waves used be
not much longer than the object being detected. Therefore, to locate an
enemy bomber having a wing span of 100 feet, one should use waves not
much more than 100 feet long. Other factors make still shorter waves
desirable, and radio waves only a few feet long, micro-waves, are found
to solve the problem admirably.

What an effective picture of the secret maneuvermgs of science this
presents! Here we have German planes loaded with destructive bombs,
five miles up in the air, swiftly feeling their way toward London by fol-

260 MATTER, ENERGY, PHYSICAL LAW

lowing a beam of radio waves sent from a station behind them in France,
Such beam flying has of course been used for years, and is a common-
place feature of most airlines in peacetime. But how is the bomber to
know when to drop its destructive cargo? From Norway or some other
point making a wide angle with the first beam another radio beam is
sent, directed to intersect the first beam directly over the target. When
signals in his earphones tell the pilot that he has reached this intersection,
he drops his load of bombs and turns to streak for home. Scientifically
designed murder, to be sure, but this is not the whole story.

Scattered all over Great Britain are short-wave radio stations which
send beams of micro-waves toward the invasion coast. When the sky
above France is clear of planes no waves are reflected to the sensitive
receivers which the British keep constantly on watch. But when a plane
rises into the air even 100 miles away, according to news reports, it reflects
back some of the micro-waves, and thus can be detected in ample time to
let interceptors take the air and be ready for it.

So important was the radio-locator that it was officially given the credit
of enabling the Royal Air Force to win the first defense of Britain. British
scientists had been working on the method for five years or longer, and
scientists everywhere are gratified that this most spectacular secret weapon
is of purely defensive value. The principle was available to the Germans
and was doubtless known by them, but this lessens its value to the British
or any other defending community not one whit.

3

There are times when a new type of camera is more important to an
army than a new type of gun, and when a good photographer is of greater
value than an able sharp-shooter. Before and during an intensive cam-
paign dozens of planes may fly over the enemy lines every day without
dropping a bomb or firing a shot. These planes contain complex oversized
cameras with which pictures of the terrain are taken, to detect any
changes in its appearance since the previous flight. The eye of the camera
has a great advantage over that of any human observer, for not only can
it absorb an entire scene in a few thousandths of a second, but it brings
back a record of what it saw which is permanent and far more revealing,
when examined slowly and in detail, than the most lingering glance of
an observer in an airplane. Films taken on two successive days can be
superposed in such a way that differences between the two — a departed
ship, a freshly bombed oil-tank, or newly camouflaged artillery — will
stand out vividly from an unobtrusive background of details common to
both photographs.

SCIENCE IN WAR AND AFTER 261

Reconnaissance planes are as vulnerable to attack as any others, so they
must fly as fast and as high as possible. Great altitude requires provision
of giant cameras, weighing several hundred pounds and costing more
than $5000 apiece, with very large lenses. To take a photograph from a
height of several miles which will reveal details as small as a man requires
the use of a lens consisting of four to six carefully shaped pieces of the
finest glass, each as large as a dinner plate. Such a camera is, in fact, a
telescope of sufficient size to delight the heart of almost any astronomer.
To provide a shutter big enough to cover such a lens, which can yet open
and close within a few thousandths of a second, requires careful scientific
designing, yet this is necessary if the photographs are to be brilliantly
sharp and clear.

When flying a reconnaissance plane, a pilot must be prepared to level
off at some definite height and fly a long, straight course while photo-
graphs are being taken. When a red light starts blinking on his instrument
panel, the pilot knows that he must fly the ship on an even keel so the
photographer can snap mile after mile of enemy territory, taking several
hundred pictures on a single roll of film. Automatic timers are sometimes
used, which click the shutter at any desired regular interval. It was com*
mon knowledge in 1941 that every day hundreds of miles of the "invasion
coast" of France was thus photographed by the Royal Air Force. From
some of the planes used for this purpose pictures were taken at an altitude
of more than five miles. By using multiple cameras in which each click
of the shutter took nine pictures through as many lenses, an area as great
as 900 square miles was photographed with each exposure.

The greater the altitude from which photographs are taken, the more
likely is the ground beneath to be partially hidden by haze. Light scattered
from this haze changes what would otherwise be a crisp and vivid picture
into one of dull uniformity and low detail. Longer waves than those our
eyes can see will be less scattered by the haze, and for this reason infra-red
photography has become of great importance in modern warfare. But
longer exposures are required when the specially sensitized film needed
for infra-red exposures is used. For this reason all the armies of the world
have been concerned with the development of infra-red film of increased
sensitivity.

As enemy territory* becomes more thoroughly protected by fighter
planes during daylight hours, it becomes increasingly difficult to take the
desired reconnaissance photographs each day. Therefore, the trend is
toward more night photography, when darkness lends to planes increased
safety from antiaircraft fire and aerial pursuit. Thus flashlight photog-
raphy has been brought into warfare, but flashlights on what a scale 1

262 MATTER, ENERGY, PHYSICAL LAW

Instead of filling with light a small room or even a huge auditorium, the
flash must illuminate the whole of outdoors!

To make an area of many square miles as bright as day, even if only
for an instant, army photographers have developed amazing flashlights
which consist of great sacks full of magnesium powder, wafted slowly to
earth by small parachutes. When the photographer wishes to take a pic-
ture, he merely tosses a sack of the powder over the side of his plane. The
parachute with which the sack is provided opens automatically, and a
fuse is set off which explodes the bomb a few seconds later, after the
powder has had time to fall the desired distance below the plane, and has
lagged sufficiently behind it. A blinding flash of light comes from the
exploding powder, and the first light from this flash strikes a phototube
on the plane, and immediately opens the shutter of the camera. Events
are automatically timed so that the shutter opens just as die landscape is
most brightly illuminated.

Camouflage — the art of concealment by merging an object with its
surroundings, or by making it appear to be what it is not — requires in-
creasing cleverness if it is to withstand successfully the searching eye of
the camera. An outstanding example of this occurred in July, 1941, when
the British published photographs showing how the Germans had at-
tempted to mislead them into bombing an innocuous block of houses in
Hamburg instead of the great railroad terminus which the British were
seeking. A bridge over a narrow body of water pointed directly at the
railway station, and this the British airmen had been using as a landmark.
The ingenious and industrious Germans covered the offending body of
water as far as the bridge with rafts carrying false houses, and a short
distance away installed a false bridge which pointed at the block destined
for sacrifice in place of the station. This device might have succeeded had
not the superposition of photographs taken before and after the alteration
revealed the shift.

The stereoscopic camera, with two lenses giving a pair of photographs
which, when viewed properly, merge into one which has depth and a
lifelike appearance of solidity, is especially valuable in revealing camou-
flage of a common type. On developing photographs of a certain enemy
flying-field, British officers found that something looked queer about a
group of airplanes packed closely in one corner of the field. The planes
looked ordinary enough when viewed from the air, and in the usual
photographs, but when a stereoscopic camera was used they appeared
quite flat and lifeless in the resulting views, instead of sticking up from
the ground as they should. It is not difficult to imagine the feelings of the
soldiers who had diligently fitted together boards in airplane shapes, laid

SCIENCE IN WAR AND AFTER 263

them on the ground, and painted them, when next day a lone bomber,
sailing over on the way to deeper-lying territory, carefully dropped two
wooden bombs on the field.

Of great value in detecting camouflage of another sort is color photog-
raphy, but strangely enough, ordinary color photography often is not
so useful as partially color-blind photography. Certain commanders were
surprised to find that one or two of their aerial observers were able to
detect four times as many camouflaged objects behind the enemy lines
as most of their observers could see. Tests showed that the abnormally
sensitive observers were color-blind.

The explanation was not far to seek. The camouflaged objects had been
carefully painted by soldiers with normal vision, who had matched their
paints in color with the surrounding green foliage. The color-blind ob-
servers, however, could not see green anyway. The greenness which, to
a person of normal vision, obliterated lesser differences between paint
and foliage, was eliminated in their eyes, leaving contrasts of redness or
blueness or tone or shade to stand out vividly.

This discovery caused many articles to be published stating that color-
blind persons would be in great demand as aerial observers. Such was not
the case, for although it is impossible to give normal color-vision to a
person who is color-blind, it is quite easy to give artificial color-blindness
to any person with normal vision. All that is needed is to equip him with
a pair of colored glasses which will absorb light of the color he is not to
see. A pair of magenta lenses will make him green-blind, for no green
light can traverse them, while blue lenses will make him red-blind. Such
colored glasses have indeed been found of great value in aerial observation,
and the really scientific camoufleur should use a spectroscope to be sure
his paints match the foliage for any light waves that may strike them.
To make the match complete with surroundings, he must include the
invisible ultra-violet and infra-red waves as well as those which the eye
can see, for the eye of the camera can see several octaves of color, whereas
the human eye can see but one. By using the proper color filters on his
scientifically equipped camera the aerial photographer can ferret out any
object in which all colors, invisible as well as visible, have not been closely
matched with those of the surroundings.

4

The tank, introduced by the British during the first World War and
since developed by other nations into a formidable juggernaut, is the
modern scientific equivalent of the armored knight of the Middle Ages.
Because spices had to be used instead of refrigerants to keep meat palata-

264 MATTER, ENERGY, PHYSICAL LAW

ble in those days, and because nothing was known about balanced diets
and vitamines, the medieval knight was rather a stunted fellow by mod-
ern standards. Most of the suits of armor preserved in museums are found
to fit men less than five feet six inches tall.

Even the most colossal knight would not have been strong enough to
carry armor of sufficient thickness to withstand modern high-power
bullets, however. To be sure, he could clothe himself and his staggering
horse in heavy armor, but once dislodged he became powerless. What
more reasonable than to substitute an automobile for the horse, use tractor
treads to cover rough ground at high speed, and put the armor on the
resulting tank instead of on the man?

The tank, like the airplane, is undergoing a period of rapid engineering
development, with scientists concerned principally in making its armor
tougher and more resistant to penetration. The larger a tank is made, the
more powerful can its engine be, and the greater the proportion of its
weight which can be used for defensive armor and offensive armament.
A bullet an inch and a half in diameter was formerly big enough to punch
holes in a tank, but now shells three inches in diameter are necessary.
Thus y-ton light tanks must give way to 25-ton medium tanks, which in
turn retire before the great 80- and zoo-ton tanks now being introduced.

There is a limit to the concentration of weight which soil can hold,
however, and if the weight of a tank is to be increased its treads must
cover a larger area. But the larger the tank the less strong does its un-
wieldly bulk become. Like the dinosaur, too large a tank is impractical,
and may ultimately collapse of its own weight. For this reason the battle-
ship of the land can never expect to compete with the battleship of the
sea, which, like the whale, is supported in depth as well as in area. Land
tanks weighing 200 tons may become practicable, but to hold 40,000 ton
tanks, a liquid is the only suitable medium.

On the sea, armor plate can really come into its own, and a solid two-
foot thickness of the toughest steel can be used to make an almost
impenetrable barrier. The resulting battleship spends most of its life in
harbor, or cruising about merely existing as a threat to lesser vessels,
waiting for the few minutes or hours when it may be in action. Then
precision of fire is of the utmost importance, and the fate of a whole navy
or nation may depend on the extra thickness of a hair by which the
muzzle of a i6-inch rifle is elevated. The enemy is to be struck if possible
before his shells can strike back; no useful development of science which
will bring this about is considered too expensive.

Between 1911 and 1941 the biggest rifles used by the navies of the
world have swelled from 12 inches in diameter to 17. This has made

SCIENCE IN WAR AND AFTER 265

possible the hurling of tons of steel 28 miles instead of a mere n, with
a vast increase in accuracy. No navy expects to hit its target at the first
salvo, which must be considered as several thousand dollars spent to find
out how the wind is blowing and how accurately certain intricate cal-
culating machines have been used to determine range and direction of
aim. In the better navies the target is supposed to be struck on the third
salvo, but the second is becoming increasingly useful as better scientific
methods of measurement are brought to bear on the problem.

To hit a target 30,0000 yards away requires careful determination of
the speed of both vessels, the angles of pitch and roll of the ship, the
barometric pressure, the humidity of the air, and even the temperature of
the powder loaded into the gun. To introduce all these factors involves
extensive computing which, if done with pencil and paper, would require
days to complete. Instead, great computing machines are used on which
the temperature of the powder can be set in with one crank, humidity
with another, range, speed, and the rest of the factors with others; then
the wheels turn and the correct setting of the guns is calculated auto-
matically within a few seconds.

Before the calculating machines can be set into operation, careful
measurements must be made with a dozen scientific instruments, and
of these the range-finder is perhaps most interesting. This has the difficult
task of measuring the distance to a target, which may be anywhere from
half a mile to thirty miles away. A modern range-finder may contain
1600 parts built with the utmost precision, and may cost as much as
$40,000. In it are glass prisms whose sides are so true that if one were
extended a distance of 80 miles, the line would be within a foot of its
correct course. A modern battleship is likely to have at least four of these
instruments, with two smaller ones pointed into the air to determine the
heights of airplanes.

There are several types of range-finders, but most involve a principle
similar to that involved in telling how far away an object is by looking
at it with both eyes open. Look at your finger held six inches from your
nose and your two eyes will be turned in sharply; now look at something
far away, and the eyes will turn so as to look in almost parallel directions.

If human beings had eyes set farther apart in their heads than they
now are, we would be able to judge distance more accurately than we
now can. In the range-finder the two eyes may be placed as much as
thirty feet apart, by using prisms to bend the light rays. Two telescopes
are set into opposite ends of a long tube, and the light which comes
through these is sent by prisms and lenses into the two eyes of the ob-
server.

266 MATTER, ENERGY, PHYSICAL LAW

One of the telescopes always looks straight ahead, but the other can
be swung through an angle to look at any object at which the other
telescope may be pointed. The observer sees his target magnified as in
an ordinary telescope, but everything above the middle of the image has
come through one telescope, and everything below through the other.
He can turn a handle until the two parts of the target come together into
one well-fitted picture; then both telescopes are pointed directly at the
target.

The turning of the handle also operates a computing machine, which
works out the mathematics involved in finding how far away an object is
when the lines of sight of the two telescopes make a certain angle. The dis-
tance to the target can be read directly from a dial which gives the correct
answer no matter where the handle is set; thus ranges up to 40,000 yards
can be read quickly to within one salvo pattern.

Range-finders are usually placed high above the deck of a battleship,
to enable them to peer over the bulge of the earth at distant objects. That
the guns are many feet below the range-finders, and must be pointed high
into the air rather than directly at the target, while they rock from side
to side as the boat rolls and pitches on the waves, does not disturb the
mechanisms charged with the duty of landing the first salvo close to the
target.

Even as early as 1935 Hitler had turned the major attention of German
scientists to the search for new developments useful in war. As his threat
developed other nations began tardily following suit. In Great Britain
the demand of the armed services for physicists and chemists became so
great in 1941 that these key scientists were not permitted to enlist as
soldiers, but were drafted for laboratory work. A great shortage of
trained scientists soon developed in all the warring countries.

Recognizing that the most powerful weapons of offense and defense
are furnished by science, the man in the street, particularly in America,
has attempted to do his bit as an inventor. Since 1918, a Naval Consulting
Board in Washington is said to have received 110,000 letters containing
suggestions for improvements in naval defense, and a National Inventors
Council was set up by the United States Government in 1940, to aid
inventors who wished to make suggestions. Some of the ideas received
were rather amazing, but a sufficient number to justify the effort of the
board of experts who sorted them out were said to have merit. . . .

A favorite field of amateur inventors in wartime is the "death ray," but
this is a device on which scientists waste no time whatever. All that is

SCIENCE IN WAR AND AFTER 267

needed to make a death ray usable is the discovery of a suitable ray.
None of the agencies known to physicists at the present time is one-
thousandth as effective in destructive action as the shell or bomb con-
taining a powerful explosive, demolishing what it strikes by the impact
of matter on matter. . , .

Discussion of the responsibility of science for ills of the human race,
of which the miseries of war are at present most striking, is to a con-
siderable degree academic. We cannot be rid of science if we would,
for science is, after all, nothing but knowledge, and it is doubtful that
the human race has the ability to keep itself in everlasting ignorance, even
if this should be proved desirable. Few persons would argue that igno-
rance is desirable, but many point out that man's spiritual development
has not kept pace with his material progress. This is obviously true, but
blame for the situation can as justly be attached to the slowness of
spiritual development as to the rapidity of material progress. Actually,
of course, the difficulty arises from the fact that spiritual development
comes only from human experience. Nature provides an automatic
compensating mechanism, such that if material progress is too rapid,
suffering results which accelerates spiritual progress.

Most of the clamor against science arises, not from real worry about
spiritual development, but because it is human nature to take benefits
for granted, while complaining loudly against accompanying disad-
vantages. It is of value to pause and note how easily these disadvantages
are exaggerated.

Much of the horror of modern warfare arises from the fact that
hundreds of millions of people, through the agency of radio, motion pic-
tures, and the daily press, are brought far closer in imagination to the
battlefield than was ever possible before. Though more people do suffer
as a result of warfare nowadays, a larger proportion of them suffer only
mentally and in anticipation.

Science, with its improved methods of communication, is responsible
for the fact that the number of things we find to worry about is increas-
ing from day to day. Science is, however, also responsible for the fact that
there is an even more rapid increase in the fraction of these terrible
things which never happen. . . .

In what are sometimes called "the good old days," war, famine, and
pestilence were considered inevitable. If half a man's family was wiped
out in a week by diphtheria, that was the will of God. Now man has
made use of his God-given opportunities to control famines which arise

268 MATTER, ENERGY, PHYSICAL LAW

from natural causes. Through science the Black Plague, cholera, yellow
fever, and a dozen other pestilences have been wiped out, and the
rest are on the way. The twentieth century may well see war, this
further "pestilence," eliminated, as through the natural sciences man
gradually raises the level of availability of the things he needs for health,
security, comfort, education, and enlightenment, by creating more and
more order in nature.

We hear much about the "good old days," but the world is growing
older every day, not younger. Opportunity knocks on every hand for him
who has ears to hear, and there is ample evidence that the best "old days"
lie ahead.

Edition of 1941

PART FOUR

THE WORLD OF LIFE

Synopsis

A. THE RIDDLE OF LIFE

WE HAVE SCANNED THE SKIES, WANDERED OVER THE
earth, penetrated the atom. As yet we have not touched the World of Life.

What is this Life? In what shadowy spot, as yet unknown, does the
transition from the dead to the quick take place? We know many of the
processes involved in living. We still do not know what life really is. W. /. V.
Osterhout, the botanical scientist who has done much to push back the
borders of the unknown, opens our discussion with The Nature of Life. He
exposes many misconceptions, although he leaves the question unsettled.
And yet, it is possible to see how living things exist in nature — their chem-
ical properties, actions and reactions, adaptation to environment, develop-
ment and multiplication. That is the theme of The Characteristics of Organ-
isms by Sir /. Arthur Thomson and Patrick Geddes.

We can also trace the course of man's belief in the spontaneous origin of
life, especially as it relates to the study of the smallest living creatures under
the microscope. The study begins with Leeuwenhoek, Paul de Kruif s ac-
count of the testy Dutchman who, looking through his homemade micro-
scopes, was the first to see those tiny "animalcules" which we call microbes.
The more he looked, the more he found — in the tissues of a whale, the
scales of his own skin, the head of a fly, the sting of a flea. He watched
them attack mussels and so realized that life lives on life. It is doubtful
whether he knew that life must always come from life or that microbes play a
dominant role in disease.

Those were discoveries that were to take centuries and test the abilities
of men like Spallanzani, Redi, Pasteur, Tyndall, Koch. We no longer think
that eels develop spontaneously in stagnant pools, that kittens (without

269

270 THE WORLD OF LIFE

parents) spring from piles of dirty clothes. The idea is so foreign to us that
we hardly believe men could have thought it possible. Yet the classic ex-
periments which disproved once and for all the doctrine of spontaneous
generation were performed no earlier than the last century by Pasteur and
Tyndall. Pasteur showed that water boiled in flasks to which the dust-filled
air was not admitted would never generate life. He showed that flasks opened
in Paris contained numerous microbes, while those opened in the Jura
mountains contained few or none. "There is no condition known today/' he
wrote, "in which you can afErm that microscopic beings came into the world
without germs, without parents like themselves."

Yet somewhere along the road, if we may believe the latest researches, life
and nonlife seem to merge. The story is told in Gray's Where Life Begins.
Here we observe viruses far smaller than anything seen by Leeuwenhoek,
made up of molecules which may be composed of thousands of atoms.
Are they alive? It depends on our definition of life. By some standards they
are, by others they are not. Perhaps further in the direction which Stanley
and others are taking, the answer lies.

The work described in this contribution by Gray is among the most
important scientific investigations of our day. No matter what the results,
however, it is doubtful whether they will resolve the conflict between the
mechanists and the vitalists. The vitalists will continue to claim that there
is something more fundamental than molecules and atoms. And, like
Pasteur in the last century, the mechanists may be counted on for new facts
to meet each new stand of their opponents.

B. THE SPECTACLE OF LIFE

Plants and animals differ from one another in myriad ways and the most
obvious is that of size. We do not often stop to analyze this difference, as
Haldane does so amusingly in On Being the Right Size. Haldane is a famous
geneticist, but he is also a writer of charm and wit. If you've ever been fear-
ful that insects might grow large enough to dominate man, or been puzzled
why mice could fall down mine shafts without injury, or wondered why there
are no small mammals in the Arctic, here is your answer. As there are dif-
ferences, so are there similarities at every level of the plant and animal king-
dom. One of the most striking is described in Parasitism and Degeneration
by Jordan and Kellogg. From single-celled plants and animals to vertebrates,
in amazing environments and through amazing metamorphoses, the para-
sites live on others; unable to find a host, they die.

Next we turn to the spectacle of life in individual species. Flowering Earth
is a long, full history of the plant kingdom. Donald Culross Peattie traces
the steps from the first single-celled life which appeared on earth, to the
algae, the Age of Seaweeds, the first plants which grew on land, the fern
forests, the conifers and cyeads, and finally to the modern floras. He tells us

THE WORLD OF LIFE 271

about the function of chlorophyll, the breathing of plants. He shows how
even the iron deposits of Minnesota were formed by microscopic plants.

T. H. Huxley's Lobster helps us "to see how the application of common
sense and common logic to the obvious facts it presents, inevitably leads us
into all the branches of zoological science." He shows us the unity of plan
and diversity of execution which characterize all animals, whethex they swim,
crawl, fly, swing from trees or walk the ground.

We travel from the simplest to the highest in animal life, beginning with
The Life of the Simplest Animals in which Jordan and Kellogg show how
single-celled animals eat, react, reproduce. Secrets of the Ocean, at high
and low tide, and under the waves, are disclosed for us by William Beebe,
with sea worms, shrimps and fishes playing roles. In The Warrior Ants by
Haskins we see many resemblances to man's own wars, much that we can
learn about the human race. Ditmars, known for his work on snakes, and
his assistant Grecnhall introduce us to one of the most exciting of all nat-
uralist adventures in The Vampire Bat. (Eckstein shows us the intelligence
of Ancestors, in apes that pull ropes arid stack boxes, that react emotionally
like men.)

C. THE EVOLUTION OF LIFE

With the great apes we have reached a stage of development which
approaches that of man, and thinking about apes leads us inevitably to a
consideration of Evolution. Here again is a theory that has changed our
entire way of thinking and in Darwinisms we obtain a brief insight into the
character of the man who originated it. Darwin and "The Origin of Species"
by Sir Arthur Keith, points out that Darwin's masterpiece is still as fresh
as when it was first written. Darwin recognized that variation in nature is
the means by which natural selection can operate. How variation occurred
he did not know. It remained for others to analyze the problem further: de
Vries and Bateson discovered that plants and animals are subject not only to
small variations but also to large and sudden "mutations." And as a result
of these inherited mutations, new varieties are swiftly bred.

It was then that biologists rediscovered the work of a forgotten Austrian
monk. Hugo Iltis, one of his compatriots now in this country, describes
Gregor Mendel and His Work with clarity and charm. These are the basic
laws of modern genetics. With the discovery of the genes and the chromo-
somes, further advances have been made. Their function is explained in
Part Five, in You and Heredity by Amram Scheinfeld, a selection that might
well have been included here, had its emphasis not been so strongly on man
himself.

So much for the main evolutionary thread. But there are important by-
ways. Julian Huxley, grandson of the great T. H. Huxley and himself a well-
known biologist, explores one of them in The Courtship of Animals, tracing
the influence of the theory of sexual selection on our interpretation of ani-

272 THE WORLD OF LIFE

mals' development and variation. In Magic Acres, Alfred Toombs describes
amusingly the effects of the laws of heredity on plant and animal breeding.
Use of our knowledge has made possible such experimental stations as that
at Beltsville, Maryland, "where the hens lay colored eggs, where the tomatoes
sprout whiskers, and the apples defy the law of gravity."

A. THE RIDDLE OF LIFE

The Nature of Life

W. J. V. OSTERHOUT

From The Nature of Life

THE ORIGIN OF LIFE

AT THE PRESENT TIME ASTRONOMERS PRESENT A
picture of the evolution of the universe which holds the imagination
captive. Some of them believe that all kinds of matter have been evolved
from one original substance, hydrogen, and that out of the material thus
created solar systems were built up. They are able to give us a fairly
satisfactory description of the processes which formed bodies like our
earth. Their account is supplemented by the geologist, who pictures the
progressive changes on the surface of the earth whereby it became fitted
to support life. The fascination of these researches is heightened when
we consider that they lead directly to a question of universal interest
which lies in the province of the biologist, How did life make its appear-
ance on our planet?

To this question an answer was given long ago by Lucretius and others,
who said that life arose out of lifeless materials. This is known as the
doctrine of spontaneous generation.

The adherents of this doctrine believed that life could arise from non-
living materials whenever the conditions were favorable. For a long time
this belief found favor with many thinkers. But the experiments of
Pasteur and Tyndall showed that if all the living organisms in a nutrient
solution were killed, and if it were kept free from contamination by
germs from without, no life subsequently appeared.

In spite of this evidence the doctrine of spontaneous generation was
revived from time to time. One of the ablest botanists of the past genera-
tion predicted that we should one day discover living forms too small to
be seen by our microscopes; these, he said, represent the earlier steps in

273

274 THE RIDDLE OF LIFE

the evolution of living forms from lifeless matter. This prediction has
been verified in so far as we now know a considerable number of such
forms (filterable viruses) some of which cause important diseases. They
cannot be detected by the ordinary microscope; they pass through filters
which retain all the ordinary bacteria. But we do not think of them as
lending support to the doctrine of spontaneous generation, since there
is no proof that they can arise from lifeless material.

How then did life originate? Are we not forced to assume that some-
where, at some time, spontaneous generation must have taken place?
Although no such process appears to occur at present we may neverthe-
less suppose that in earlier geological epochs and under more favorable
conditions it might have happened. And if, as Arrhenius supposes, life
can originate on any appropriate heavenly body • and spread thence to
other bodies we have an immense extent of time and space in which to
find conditions favorable to the origin of life. It may be that such condi-
tions have never existed on our planet and perhaps have occurred but
rarely in the history of the universe. It is not impossible, however, that
we may learn of their occurrence, in the past or the present, since the
spectroscope gives us accurate information about the composition of
heavenly bodies and, in the case of distant stars, tells us what they were
like thousands of years ago. If we do not observe on the earth the con-
ditions necessary for the origin of life we may perhaps hope to find them
in some of these heavenly bodies which might differ sufficiently from
our planet to provide the necessary combination of factors.

Arrhenius thinks that spores of bacteria might be carried to the upper
limits of our atmosphere and thence be expelled into interstellar space,
poetically called the "ether sea." There the spores might be driven away
from the sun by the action of light, which might exert on such small
bodies pressure sufficient to carry them to the outermost limits of our
solar system. Thus interstellar space might conceivably be peopled with
spores which could come in contact with any heavenly body that had
reached a stage in its development at which life could be supported.

It has been objected that the spores might be killed by intense cold,
dryness, lack of air, or the action of light. But some spores are resistant
to these influences and it is by no means certain that they could not
survive a long time in interstellar space.

The theory of Arrhenius stands out as a stimulating example of specu-
lative thought. It is inspiring to picture life, taking flight from worlds
outworn to fresh fields in younger planets, and persisting as long as the
universe can harbor it, in cycle on cycle of endless progress. We may
admire this beautiful theory as a splendid achievement of the creative

THE NATURE OF LIFE 275

imagination but we cannot at present prove or disprove its correctness.
If it should one day turn out to be true? it will greatly widen the possi-
bility of finding appropriate conditions for the origin of life.

GROWTH

Leaving this riddle of the origin of life, let us turn to another question
of equal importance. What new factor entered into the universe with the
first appearance of life? We may perhaps put this in a more concrete
form by asking, How may we distinguish the living from the dead?

It may not seem very difficult to answer this question but the matter
is less simple than might at first appear. As an illustration let us take
some dry seeds. Their appearance does not tell us whether they are alive
or dead. Most people if called upon to decide would plant them, and
use growth as a test of life.

If we are to employ growth in this manner it is important to have a
clear understanding of what it means. Growth is often thought of as
comprising the whole development of the organism. Ordinarily the
life cycle of an animal or plant begins with a single cell, which by
repeated division produces a mass of cells. The form of the organism
then changes, and its parts become differentiated so as to perform dif-
ferent functions.

The question now arises, What is essential to the conception of growth ?
A simple illustration will make it clear that growth may go on without
cell division, change of form or color, differentiation, or assimilation of
food. A small, spherical, green cell, desiccated by the drying up of a pool
in which it has lived, and blown about by the wind, eventually falls into
water. Such a cell often remains alive and when it again finds itself in
water begins to grow. No one will deny that this is genuine growth but
it certainly need not possess all the features which we have enumerated.
In the first place cell division may be absent for a long time. Many cells
increase enormously in size and never undergo division. A nerve cell
may grow to be many hundred times its original length without divid-
ing; and it will continue to function for years and finally die without
any sign of nuclear or cell division. We cannot therefore regard cell
division as essential to the conception of growth, though in most cases
it accompanies growth and is advantageous because it provides separate
compartments in which the diverse processes of the organism can go on
without mutual interference.

There may be no change of form or color in the green cell of which
we are speaking, since it may remain green and spherical while growing.
Nor is there any reason to suppose that in general a change of form is

276 THE RIDDLE OF LIFE

essential to growth. It commonly occurs but is by no means indispensable.
Nor is it necessary that a differentiation of the organism into unlike parts
should take place in order that a process may be called growth. Such
differentiation is not observed during the growth of the simplest cells,
such as bacteria, which may have at the beginning all the parts they
possess when growth is complete.

Of especial interest is the assimilation of food and the building up of
those substances which are characteristic of each kind of organism. We
know that seeds can grow for weeks in the dark, absorbing nothing
except air and water. Under these circumstances the food which is stored
in the seed steadily decreases. A kidney bean grown under such condi-
tions may reach a height of four feet and gain in weight more than fifty
fold. Yet this great gain in weight is wholly due to the water it absorbs.
Its dry matter steadily decreases during the whole period, undergoing a
process of combustion which results in continually giving off carbon
dioxide to the air. In this way nearly half the dry material may disap-
pear during growth.

It is true that growth must eventually cease under these circumstances
but the fact that it can go on for so long although the plant takes in no
food shows that increase in dry weight is not necessary for growth.

Since we find that growth may occur without increase in dry weight,
change of form or color, cell division, or differentiation, we may ask,
What is really essential to growth ? The answer seems to be, An increase
in size due to the absorption of water. Let us now look into this more
closely.

It is a very striking fact that when dry seeds are planted in moist soil
the dead seeds appear to grow in the same way as the live ones during
the first few hours. We find, however, that a dead seed soon stops
growing while the living one continues. This suggests that the water is
not absorbed in quite the same manner in the two cases. Absorption of
water may occur in two ways, which are known as imbibition and
osmosis. Imbibition is the process which occurs when a piece of dry
wood is placed in water. The water is taken up into minute pores, other
processes follow, and the result is a swelling which, though short-lived,
can develop great pressure. At one time granite blocks were split open
by drilling holes in a straight line and inserting plugs of dry wood. These
were covered with wet rags, the wood absorbed water and the granite
block was split. Careful measurements show that starch may develop a
pressure of thirty thousand pounds per square inch in taking up water.
It is therefore no wonder that a ship loaded with rice is quickly burst
asunder if water reaches the cargo.

THE NATURE OF LIFE 277

In osmosis water is absorbed in a different way. This may be illustrated
by the story of the good abbe who hid a skin of wine in the cistern of
the abbey. When the monks developed an unusual taste for water he
investigated and found to his horror that the skin had burst. The wine
had taken up water through the skin because it contained substances
which attract water (the word "attract" is here used in a somewhat
figurative sense). In the living cell there is a protoplasmic membrane
which corresponds to the skin, and inside this a solution which attracts
water. As water is taken up the protoplasmic membrane is stretched,
and if there is a cellulose wall outside the living membrane it shares the
same fate. The living membrane can be stretched almost indefinitely
because the cell can furnish it with new material so that it can continue
to expand without rupture. At the same time the cell can produce
substances which attract water. It is therefore possible for growth to
continue indefinitely.

The growth of the dead seed is due to imbibition while that of the
living seed is due during the first few hours principally to imbibition,
after that principally to osmosis. We should therefore expect that the
dead seed would soon stop growing while the living one would continue.

Osmosis does not ordinarily develop so much pressure as imbibition but
it is supposed that the pressure it produces in the living cell may reach
three hundred pounds per square inch or even more: this is as much as
is commonly found in steam boilers. It is sufficient to drive ferns up
through macadamized roads and concrete sidewalks and to enable toad-
stools to lift heavy flagstones.

Let us now consider whether there is anything in growth which can
be used as a criterion of life. We have tried first of all to discover what
is essential to growth. Such things as cell division, change of form, dif-
ferentiation, and the assimilation of food may be taken away, and yet
growth may go on for a long time. One process cannot be dispensed with,
the absorption of water. This appears to be the essential thing.

If growth consists of the absorption of water can this serve as a test
to distinguish the living from the dead? As we have seen, absorption
of water takes place by imbibition or by osmosis. Imbibition cannot
serve as a mark of distinction for it goes on in the same way in dead and
in living seeds. If we are to employ growth as a test of life it can be only
on the ground that osmosis is in some way peculiarly characteristic of
living cells. Let us see whether this is the case.

One way of attacking this question is to attempt to make an artificial
cell which will act like the living. We may employ for this purpose two
solutions, A and 5, such that a drop of A introduced into a vessel con-

278 THE RIDDLE OF LIFE

taining B will react with it and form a membrane which is impervious
to both A and B, but is permeable to water. We have now what we may
for convenience call an artificial cell. It consists of a membrane in the
form of a rounded sack which completely incloses a drop of the solution
A and which is surrounded by the solution B. If now solution A is more
concentrated than solution B water will be attracted by solution A and
will pass into the artificial cell which in consequence will expand and
stretch the membrane. Under the proper experimental conditions this
may continue for a long time.

We may employ for such experiments a great variety of materials, as
copper salts in a solution of potassium ferrocyanide, metallic salts of
various kinds in a solution of water glass, or tannic acid in a solution
of gelatin. In some cases the artificial membrane expands by repeated
rupture and repair, in others it is steadily stretched without rupture, and
at the same time strengthened by the deposit of new material. The
protoplasmic membrane might conceivably expand in either way. It is
not certain which method is followed.

In both the living and the artificial cell growth is quickened by increase
of temperature. In the living cell there is an upper limit of temperature
beyond which no growth takes place. This seems to be due to the proteins
of the living cell. If we could employ such proteins in the membrane of
the artificial cell we might obtain a similar result.

The rate of growth depends, in the living as in the artificial cell on
the supply of substances within the membrane which can attract water.
In the case of the living cell these are mostly sugars, organic acids, salts,
and so on, and we can employ these same substances in the artificial
cell. In the living cell we often find starch, which takes little part in
attracting water but which may be gradually transformed into sugar
which attracts water actively. In the same way we may place starch in
the artificial cell and have it slowly transformed to sugar and thereby
cause the cell to take up water.

If the artificial cell is placed in a solution which is more concentrated
than that inside the cell, water is attracted from the cell to the outside
solution and in consequence the cell shrinks. This is also true of the living
cell. If it is growing in tap water it can be made to shrink by putting
it into a sugar solution which withdraws water. If replaced in water it
again expands. Since we regard this as growth, the shrinkage may be
looked upon as the reversal of growth. We find that many living cells
may be made to grow and shrink several times in succession, just as in
the case of the artificial cell.

If the outside solution is concentrated enough to draw water out of

THE NATURE OF LIFE 279

the cell it may nevertheless prevent water from going in and so check
growth in proportion to its concentration. Consequently by varying the
concentration we may accurately control the rate of growth.

We might go on to discuss other points of resemblance between the
growth of the living and the artificial cell but this hardly seems neces-
sary. If we accept the definition of growth given above it is clear that
the artificial cell furnishes an imitation which is sufficiently complete for
our purpose. We must therefore conclude that there is nothing in the
absorption of water by the living cell, either by imbibition or by osmosis,
which differs essentially from these processes as found in non-living
systems.

In conclusion we may ask whether life can go on in the absence of
growth. We know that certain things may be temporarily taken away
from living matter without taking away life itself. Is growth one of
these? Certainly the resting seed lives for years without any sign of
growth. This is also true of many animal cells. The suppression of all
signs of growth does not in any way involve the suppression of life.
Even when placed in moist soil with all external conditions favorable
some living seeds remain quiescent for months or years before they start
to grow.

Hence it seems possible to have life without growth and growth with-
out life.

Our analysis of the process of growth illustrates the method which
biological investigation must very commonly pursue. The biologist wishes
to study living matter in the same manner that the chemist and physicist
study their material. His first task is observation, after that he must
analyze in order to discover what properties are essential and what are
merely accompanying phenomena. He need not attempt to explain these
phenomena, for, after all, we can never arrive at ultimate explanations.
But he can attempt to predict and control. The physicist cannot explain
electricity but he can predict and control electrical phenomena. In the
same way the biologist hopes to be able to predict, and control life
phenomena. One method which he finds particularly useful is to make
artificial imitations which closely resemble the phenomena he is studying.
If he succeeds in this he may find the fundamental laws of physics and
chemistry on which life phenomena are based.

7924

The Characteristics of Organisms

SIR J. ARTHUR THOMSON and PATRICK GEDDES

From Life: Outlines of General Biology

FROM A COMMON-SENSE POINT OF VIEW THE
apartness of living creatures from non-living things seems con-
spicuous. It appears almost self-evident that an organism is something
more than a mechanism. But when we inquire into the basis of this
common conviction we usually find that the plain man is thinking of the
highest animals, such as horses and dogs, in which he recognises incipient
personalities, in a world quite different, he says, from that of machines,
or from that of the stars or stones. His conviction rests on his recognition
of them as kindred in spirit; but he hesitates when we ask him to consider
the lower animals, down to corals and sponges, and still more when
we ask what he thinks about plants. In such relatively simple organisms
as corals and seaweeds, he detects no mental aspect; and apart from this,
they show him but little of that bustling activity which is part of his
picture of what "being alive" means. Thus, while he was sure that dog
and wheelbarrow were separated by a great gulf, he is not so convinced
about the difference between a coral and a stone. It is, therefore, for the
biologist to explain as clearly as he can the fundamental characteristics of
all living creatures. . . .

PERSISTENCE IN SPITE OF CEASELESS CHANGE

The symbol of the organism is the burning bush of old; it is all afire,
<iut it is not consumed. The peculiarity is not that the organism is in
continual flux, for chemical change is the rule of the world; the charac-
teristic feature is that the changes in the organism are so regulated
that the integrity of the system is sustained for a longer or shorter
period. That excellent physiologist, Sir Michael Foster, used to say that
"a living body is a vortex of chemical and molecular change"; and the

280

THE CHARACTERISTICS OF ORGANISMS 281

image of a vortex expresses the fundamental fact of persistence, in spite
of continual flux.

Here it is fitting to quote one of the cfassic passages in modern bio-
logical literature, what Huxley said of the vital vortex in his Crayfish
(1880, p. 84):

"The parallel between a whirlpool in a stream and a living being,
which has often been drawn, is as just as it is striking. The whirlpool is
permanent, but the particles of water which constitute it are incessantly
changing. Those which enter it, on the one side, are whirled around and
temporarily constitute a part of its individuality; and as they leave it on
the other side, their places are made good by new-comers. . . .

"Now, with all our appliances, we cannot get within a good many
miles, so to speak, of the crayfish. If we could, we should see that it was
nothing but the constant form of a similar turmoil of material molecules
which are constantly flowing into the animal on the one side, and
streaming out on the other."

The comparison has great force and utility; it vivifies the fundamental
fact that streams of matter and energy, such as food and light, are
continually passing into the organism, and that other streams are con-
tinually passing out, for instance in the form of carbon dioxide and
heat. On the other hand, the comparison has its weakness and possible
fallaciousness; for it is too simple. It does not do justice to the character-
istic way in which the organism-whirlpool acts on the stream which is
its environment; it does not do justice to the characteristic way in which
the organism-whirlpool gives rise to others like itself. No one who believes
that higher animals (at least) have a mental aspect that counts, can
agree that the organism is exhaustively described as "nothing but the
constant form of a turmoil of material molecules." And even if the
mental aspect be ignored, there remains as a fundamental characteristic
that the "constant form" is secured by organic regulation from within.
Life is nothing if not regulative.

Biology has come nearer the crayfish since Huxley's day, and it is
profitable to linger over the fact that the living creature persists in spite of
its ceaseless change. As a matter of fact it persists because of the self-
repairing nature of its ceaseless change. Hence we give prominence to
this material flux.

METABOLISM OF PROTEINS. — Proteins are nitrogenous carbon-compounds
that are present in all organisms, and, apart from water, of which
there is seldom less than 70 per cent., they constitute the chief mass of
the living substance. They are intricate compounds, with large mole-

282 THE RIDDLE OF LIFE

cules, which are built up of groups of amino-acids, i. e. fatty acids in
which one of the hydrogen atoms is replaced by the ammo-group NHs
Proteins, such as white of egg, or the casein of cheese, or the gluten of
wheat, do not readily diffuse through membranes; they occur, as will
be afterwards explained, in a colloid state, and although some, e. g.
haemoglobin, the red pigment of the blood, are crystallisable, they are
not known in a crystalloid state in the living body. Though relatively
stable bodies, proteins are continually breaking down and being built
up again within the cells of the body, partly under the direct influence
of ferments' or enzymes.

There are constructive, synthetic, upbuilding, or winding-up chemical
processes always going on in the living organism, which are conveniently
summed up in the word anabolism, applicable, of course, to the synthesis
of other carbon-compounds besides proteins, notably to the formation
of carbohydrates in the sunned green leaf. There are also disruptive,
analytic, down-breaking, running-down chemical processes always going
on in the living organism, which are conveniently summed up in the
word \atabolism — applicable, of course, to other carbon-compounds be-
sides proteins, as, for example, to the breaking down of amino-acids into
fatty acids and ammonia. To include the two sets of processes, anabolism
and katabolism, the general term metabolism is used. It is convenient to
use this term in a broad way, as the equivalent of the German word
"Stoffwechsel" (change of stuff), to include all the chemical routine of
the living body. The present point is that living always involves the
metabolism of proteins; and that this is so regulated that the living
creature lives on from day to day, or from year to year, even from century
to century.

There is intense activity of a simple kind when the fragment of
potassium rushes about on the surface of the basin of water, but it differs
markedly from the activity of the Whirligig Beetle (Gyrinus) that
swims swiftly to and fro, up and down in the pool. The difference is
not merely that the chemical reactions in the beetle are much more in-
tricate than is the case with the potassium, and that they involve
eventually the down-breaking and up-building of protein molecules.
The big difference is that the potassium fragment soon flares all its
activity away and changes into something else, whereas the beetle retains
its integrity and lasts. It may be said, indeed, that it is only a difference
in time, for the beetle eventually dies. But this is to miss the point. The
peculiarity we are emphasising is that for certain variable periods the
processes of winding-up in organisms more than compensate for the
processes of running down. A primitive living creature was not worthy

THE CHARACTERISTICS OF ORGANISMS 283

of the name until it could balance its accounts for some little time,
until it could in some measure counter its katabolism by its anabolism.
Perhaps it was only a creature of a day, which died in the chill of
its first night, probably after reproducing its kind; but the point
is that during its short life it was not like a glorified potassium
fragment or a clock running down. It was to some extent winding itself
up as well as letting itself run down. It was making ends meet
physiologically.

In the immense furnaces of the stars, with unthinkably high tem-
peratures, it may be that hydrogen is being lifted up into more complex
forms of matter, but on the earth all the chemico-physical clocks are
running down. . . .

In the little corner of the universe where we move, we are living
in a time of the running down of chemico-physical clocks. But the
characteristic of living organisms is that they wind themselves up. . . .

COLLOIDAL PROTOPLASM. — The accumulation of energy in organisms
is mainly effected by storing complex chemical substances, not merely as
reserves in the ordinary sense, like the plant's starch and the animal's fat,
but in the living substance itself in the form of increased protein material.
The chemical formula of egg-albumin, to take a familiar protein, is often
given as Ci428H2244N364O4G2Si4; and this hints at the complexity of
these substances. In the strict sense, protein material does not form
definite stores in animals, though it is a common reserve in the seeds of
plants, but it accumulates as the amount of living matter increases. The
potential chemical energy of the complex carbon-compounds found in
living cells is particularly valuable because the living matter occurs in a
colloidal state. Of this it is enough to say that a watery "solution" holds
in suspension innumerable complex particles, too small to be seen, even
with the microscope, but large enough to have an appreciable surface.
The particles do not clump together or sink because each carries an
electric charge, and like charges repel one another. . . .

SPECIFICITY. — Each kind of organism has its chemical individuality,
implying a specific molecular structure in some of the important constit-
uents, and a corresponding routine of reactions. This is particularly true
of the proteins, and there are probably special proteins for each genus
at least. There is chemical specificity in the milk of nearly related
mammals, such as sheep and goats; and, as Gautier showed in detail, in
the grape-juices of nearly related vines. A stain due to the blood of a
rabbit can be readily distinguished from a stain due to the blood of a
fowl or of a man. More than that, as Reichert and Brown have demon-
strated conclusively (1909), the blood of a horse can be distinguished from

284 THE RIDDLE OF LIFE

that of an ass. The crystals of the haemoglobin or red blood pigment of a
dog differ from those of a wolf, from which the dog evolved, and
even from those of the Australian dingo, which seems to be the result
of domesticated dogs going wild and feral. Even the sexes may be
distinguished by their blood, and there are two or three cases among
insects where the colour of the male's blood is different from the
female's. The familiar fact that some men cannot eat particular kinds of
food, such as eggs, without more or less serious symptoms, is a vivid
illustration of specificity. It looks as if a man was individual not merely
in his finger-prints, but as to his chemical molecules. Every man is
his own laboratory. Modern investigation brings us back to the old
saying: "All flesh is not the same flesh; but there is one kind of flesh of
men, another flesh of beasts, another of fishes and another of birds." . . .
To some who have not looked into the matter it may seem almost
preposterous to speak of a particular protein for every genus at least.
But the work of Emil Fischer and others has shown that there is incon-
ceivable variety in the groupings and proportional representations of the
twenty-odd amino-acids and diamino-acids which constitute in varied
linkages the complex protein molecules. There must be a million million
possibilities and more. As there are about 25,000 named and known
species of Vertebrates and about 250,000 (some would say 500,000)
named and known species of Invertebrates, there may readily be
particular proteins for every species of animal, leaving plenty to spare
for all the plants.

GROWTH, MULTIPLICATION, AND DEVELOPMENT

The organism's power of absorbing energy acceleratively, and of ac-
cumulating it beyond its immediate needs, suggests another triad of
qualities — growing, reproducing, and developing, which may be profit-
ably considered together. . . .

GROWTH. — The power of growth must be taken as a fundamental
characteristic of organisms, for it cannot as yet be re-described in
chemical and physical terms. The word is a convenient label for a
variety of processes which lead to an increase in the amount of living
matter, and while there are chemical and physical factors involved in
these processes, we are bound in the present state of science to admit
that growth depends on the veiled tactics of life. Its results are extraor-
dinary achievements, which would be astounding if they were not
so familiar. From a microscopic egg-cell there develops an embryo-plant
which may grow, say, into a Californian "Big Tree" — perhaps three
hundred feet in height and over three thousand years old. A frog is

THE CHARACTERISTICS OF ORGANISMS 285

about three or four inches in length, its egg-cell is under a tenth of an
inch in diameter; "the mass of the human adult is fifteen billion times
that of the human ovum." In the strict sense growth means an increase
in the amount of the organism's living matter or protoplasm, but it
is often associated, as in a cucumber, with great accumulation of water;
or, as in the case of bone, with the formation of much in the way of
non-living walls around the living cells. . . .

The indispensable condition of growth is that income be greater than
expenditure. A variable amount of the food-income is used to meet
the everyday expenses of living; the surplus is available for growth; and
this must be understood as including, besides increase in size, that im-
perceptible growth which brings about the replacement of worn-out
cells by fresh ones. Green plants are great growers when compared with
animals — the Giant Bamboo may grow a foot in a day — and that is
mainly because they get food-materials at a low chemical level, that is
to say from the air and the soil-water. Helped by its chlorophyll, the
green plant is able to use part of the energy of the sunlight that bathes
its leaves to build up sugars, starch, and proteins, first of course for
its own maintenance and for its growth, thereafter for "reserves," vari-
ously stored for its own future, or that of its offspring. On this highly
profitable synthesis and storage in the plant, the growth of all animals
depends — directly in the case of the sheep and other herbivores, in-
directly in the case of the tiger and other carnivores.

Food is thus obviously an indispensable condition of growth; but
there are some puzzling cases, e. g. the striking growth behaviour of
a single fragment of Planarian worm, without food-canal, and thus in-
capable of ingesting food; yet soon growing a new head and posterior
end, fashioning itself anew into a perfect miniature worm. Here, as in a
germinating seed, there must have been absorption of water and utilisation
of the previous material in a less condensed form.

Another curious form of growth is expressed in the replacement of
lost parts, such as the claw of a crab, or the arm of a starfish; and here
again the body yields supplies. One of the most extraordinary instances
of such replacement-growth is that seen annually when the stag, having
dropped his antlers, rapidly grows a new set, which, in the monarch,
may weigh seventy pounds!

The great majority of animals have a definite limit of growth,
an optimum size, which is normally attained by the adult and rarely
exceeded; so there must be some method of growth-regulation. On the
other hand, some fishes and reptiles continue growing as long as they

286 THE RIDDLE OF LIFE

live, just like many trees; and this shows that a limit of size is not
fundamentally insisted on by nature.

When we think of giants and dwarfs, and of the rarity of their
occurrence, the idea of regulation is again suggested. So also when we
observe the occurrence — yet rare occurrence — of monstrous growths
among animals, we see that growth is essentially a regulated increase in
the amount of adjustment of living matter. By what means is such
regulation affected? The modern answer to this question is twofold.
Regulation is partly due to certain hormones (chemical "messengers")
which are produced in "ductless glands" and distributed by the blood.
Thus the hormones of the thyroid gland, and those of the pituitary body,
have, among other functions, that of growth-control. Again, it has
been shown that parts where metabolism is most intense, e. g. the
growing point of a stem, exert a sway or dominance over the growth
of other parts, as we shall see more fully later.

Another feature of growth is its periodicity. All are familiar with the
rings of growth on the cut stem of a tree, which mark its years, through
the well-marked seasonal alternation of spring and summer wood, which
are different in texture. This instance is no exceptional case, but a
vivid illustration of the rhythmic periodicity of life. The same is seen
in the zoning of fish-scales and the barring of birds' feathers, and in the
familiar growth-lines on the shells of the seashore.

Familiarity is apt to dull our eyes to the marvel of growth — the
annual covering of the brown earth with verdure; the desert blossoming
as the rose; the spreading of the green veil over the miles of wood-
land; the bamboo rising so quickly that one can see it grow; the Sequoia
or Big Tree continuing to increase in bulk for three thousand years; the
coral-polyps adding chalice to chalice till they form a breakwater a
thousand miles long; the Arctic jellyfish becoming bigger and bigger
till the disc is over seven feet in diameter and the tentacles trail in
the waves for over a hundred feet. Again, many an animal egg-cell
develops into a body that weighs billions of times as much as its
beginning; and this is far exceeded in the growing up of giants — like
a Blue Whale, eighty-five feet in length, or an Atlantosaurus with a
thigh-bone as high as a tall man.

MULTIPLICATION. — The corollary of growth is multiplication, a term
that we are using here in preference to the more general word repro-
duction, which includes the whole series of functions concerned with
giving rise to other organisms. Multiplication essentially means separating
off portions or buds, spores or germ-cells, which start a new generation.
In the asexual method of separating off large pieces, the connection

THE CHARACTERISTICS OF ORGANISMS 287

with growth is obvious; multiplication occurs as a consequence of
instabilities which follow overgrowth. As Haeckel said long ago, repro-
duction is discontinuous growth. Its externally simplest form is seen in
the division of an overgrown unicellular organism, yet in the everyday
division of most of the cells of plants and animals, this has been elabo-
rated into an intricate process, which secures that each of the two
daughter-cells gets a meticulously precise half of everything that is in
the parent-cell.

The connection between growth and cell-division is not far to seek.
Spencer, Leuckart, and James pointed out independently that as a cell
of regular shape increases in volume, it does not proportionately increase
in surface. If it be a sphere, the volume of cell-substance or cytoplasm to
be kept alive increases as the cube of the radius, while the surface,
through which the keeping alive is effected, by various processes of
diffusion, increases only as the square. Thus there tends to set in a
hazardous disproportion between volume and surface, and this may set
up instability. The disturbed balance is normally restored by the cell
dividing into two cells. . . .

In cases of sexual reproduction, where germ-cells are separated off to
start a new generation, the relation between growth and multiplication
is not, of course, so direct as in cases of asexual reproduction by fission or
fragmentation. It may be pointed out that reproduction often occurs at
the limit of growth, and that there is a familiar seesaw between feeding
and breeding periods, between leafing and flowering, between nutrition
and reproduction.

The division of a cell is one of the wonders of the world. Bateson
wrote: "I know nothing which to a man well trained in scientific
knowledge and method brings so vivid a realisation of our ignorance of
the nature of life as the mystery of cell-division. ... It is this power of
spontaneous division which most sharply distinguishes the living from
the non-living. . . . The greatest advance I can conceive in biology
would be the discovery of the instability which leads to the continued
division of the cell. When I look at a dividing cell I feel as an astronomer
might do if he beheld the formation of a double star: that an original
act of creation is taking place before me."

In the present youthful condition of biology it is wise to return
at frequent intervals to concrete illustrations. We need the warmth of
actual facts to help us to appreciate the quality of reproductivity which
we are only beginning to understand. In one day the multiplication of
a microbe may result in a number with thirty figures. Were there an
annual plant with only two seeds, it could be represented by over a

288 THE RIDDLE OF LIFE

million in the twenty-first year. But a common British weed (Sisymbrium
officinal?) has often three-quarters of a million of seeds, so that in
three years it could theoretically cover the whole earth. Huxley calculated
that if the descendants of a single green-fly all survived and multiplied,
they would, at the end of the first summer, weigh down the population
of China. A codfish is said to produce two million eggs, a conger eel ten
millions, an oyster twenty-millions. The starfish Luidia, according to
Mortensen, produces two hundred million eggs every year of its life.

DEVELOPMENT. — In active tissues, like muscle or gland, wear and
tear is inevitable, especially in the less labile parts of the cells — the
furnishings of life's laboratories, such as the for the most part ultra-
microscopic films that partition the cyptoplasm into areas. When the
results of the wear and tear over-accumulate, they tend to depress
activity and in time to inhibit it; and this means ageing, towards death.
But this decline of vitality may be counteracted by rejuvenescence-
processes in the ageing cells, or by the replacement of worn-out cells by
new ones. In some cases the hard-worked cells go fatally out of gear,
as in the brain of the busy summer-bee, which does not usually survive
for more than six or eight weeks. In other cases, as in ordinary muscle,
the recuperation afforded by food and rest is very perfect, and the same
cell may continue active for many years. Such cells are comparable to
the relatively simple unicellular animals, like the amoebae, which recuper-
ate so thoroughly that they evade natural death altogether. In another
set of cases, e. g. the lining cells of the stomach, or the epithelium
covering the lips, the senescent cells die and drop off, but are replaced by
others. The outer epidermic layer of the skin (the stratum corneum) is
continually wearing away, and as continually being replaced by con-
tributions from the more intensely living and growing deeper stratum
(the stratum Malpighii). Similarly at the tip of a rootlet there is a
cap of cells which are always dying away and being replaced from the
delicate growing point which they protect. From such replacement of cells
there is an easy transition to the re-growth of lost parts. The starfish
re-grows its lost arm, the crab its claw, the snail its horn, the earthworm
its head. From cells below the plane of separation there is in each
case a regulated growth, which replaces what has been lost. We have
already mentioned a very striking instance, in which regrowth is normal,
and in organic and seasonal rhythm independent of any violence from
without — namely, the re-growth which gives the stag new antlers to
replace those of the previous year. . . . The needful renewal of
embryonic tissue is rarely seen, unless there be some recurrent need for it.
Most lizards can re-grow their long tail if that has been snapped off by a

THE CHARACTERISTICS OF ORGANISMS 289

bird or surrendered in fear or in battle, but the chameleon which keeps
its tail coiled round the branch, has not unnaturally lost this power.
Long-limbed animals like crabs, and starfishes with their lank arms,
have great regenerative capacity, in striking contrast to the compact
and swiftly moving fishes, which cannot even replace a lost scale! The
recurrence of non-fatal injuries is not common among the higher
animals, so their power of regenerating important parts has waned.
Enough of this, however; our present point is that the regeneration of
lost parts illustrates a renewal of that regulated growth of complicated
structure which is characteristic of embryonic development. Out of
apparently simple cells at the stump of a snail's horn, the whole can be
regrown, including the eye at the tip; and this may occur not once only,
but forty times. From the broken portion of a Begonia leaf there buds a
complete plant — to root and shoot and flower. From such reconstruc-
tion there is but a step to the asexual multiplication of many plants and
animals — whether by the bulbils of the lily, the budding of the hydra
in the pond, or the halving of the Planarian worm. When the tail-half
of the dividing Planarian worm proceeds to differentiate a new head,
with brain-ganglia, eyes, and mouth complete, there is an obvious
development — the formation of new and complex structures out of the
undifferentiated and apparently simple. . . .

In his discussions of the characteristics of living creatures, Huxley was
wont to lay emphasis on what he called "cyclical development." Within
the embryo-sac, within the ovule, within the ovary of the flower, a
miniature plant is formed by the division and re-division of the
fertilised egg-cell. The ovule becomes a seed; and this, when sown,
a seedling. By insensible steps there is fashioned a large and varied
fabric, of root and shoot, of leaves and flowers. But sooner or later, after
this development is complete, the grass begins to wither and the flower
thereof to fade. In the case of an annual plant, there is soon nothing
left but the seeds, which begin the cycle anew. . . .

Among animals the egg-cell, in many cases microscopic, divides and
redivides, and an embryo is built up. Division of labour sets in among
its units. . . . Some cells become nervous, others muscular, others
glandular, others skeletal; and so the differentiating process continues.
Hereditary contributions from parents and ancestors find expression,
some of fundamental importance and others relatively trivial; the past
lives on in the present; often the individual shows, in varying degree,
evidence that it is "climbing up its own genealogical tree." Sometimes the
embryo develops steadily and directly into the likeness of its kind, as
in birds and mammals, with only traces of circuitousness, such as

290 THE RIDDLE OF LIFE

notochord and gill<lefts disclose — tell-tale evidence of the lien the past
continues to hold on the present. . . .

BEHAVIOUR, ENREGISTRATION, AND EVOLUTION

A third triad of qualities which are distinctive of the living organisms
may be summed up in the words behaviour, registration, and evolution,
in which as in previous triads an underlying unity may perhaps be dis-
cerned.

BEHAVIOUR. — Herbert Spencer spoke of life as "effective response,"
and from the amoeba upwards we recognize among animals the power
of linking actions in a chain so that the result is behaviour — always
purposive and in the higher reaches purposeful. Responses are common
in the inorganic world — from gentle weathering to volcanic explosion —
but non-living things do not show the living creature's power of
reacting in a self-preservative way. Among plants, for various reasons,
such as the fixed habit of the great majority and the enclosing of the
cells in cellulose, there is relatively little exhibition of that purposive
"doing of things" which we call behaviour, but we must not forget the
insurgent activities of climbing plants or the carnivorous adventures
of Venus's Fly-trap and the Sundew.

ENREGISTRATION. — A bar of iron is never quite the same after it has
been severely jarred; the "fatigue of metals" is one of the serious risks of
engineering; the violin suffers from mishandling. But these are hardly
more than vague analogies of the distinctive power that living creatures
have of enregistering the results of their experience, of establishing
internal rhythms, of forming habits, and of remembering. As W. K.
Clifford put it: "It is the peculiarity of living things not merely that
they change under the influence of surrounding circumstances, but that
any change which takes place in them is not lost, but retained, and, as it
were, built into the organism, to serve as the foundation for future
action." ... In various forms this is a distinctive feature of the
living creature.

EVOLUTION. — In the attempt to understand organisms we must en-
visage them as a whole, we must see them in the light of evolution.
Thus it must be recognized as characteristic of organisms that they
give origin to what is new; they have evolved and evolution is going
on. There is variability in the crystalline forms which the same substance
may assume; the modern physicist tells us of "isotopes" like the different
kinds of "lead," which have the same chemical properties, yet differ in
the structure of the nucleus of their atoms; the modern chemist even
assures us of the transmutation of elements, thus not a little justifying the

THE CHARACTERISTICS OF ORGANISMS 291

medieval alchemist's dream and quest. . . . Yet these are only suggestive
analogies; for the living organism is the supreme, though uncon-
scious, creative chemist.

No doubt there are species that show nowadays little or no variation;
there are conservative living types that seem to have remained the same
since their remains were first buried in the mud millions of years ago,
but the larger fact is variability. In multitudes of cases the offspring show
something new.

What impressions of variability we get at a "show" — whether of dogs
or pigeons, roses or pansies! Here we have, as it were, the fountain of life
rising high in the air — blown into strange forms by the breeze, yet modu-
lated, to its own ceaseless waxings and wanings, by varying pressures
from its source. Two hundred different "forms" or varieties are described
by Jordan in one of the commonest of small Crucifers, the whitlow-grass
or Draba verna\ and these are no longer fluctuating but breeding true.
Again, Lotsy speaks of the bewildering diversity exhibited by a series of
about two hundred specimens of the Common Buzzard (Buteo buteol)
in the Leyden Museum, "hardly two of which are alike." . . .

GLIMPSES OF LIFE

Our discussions of living creatures are apt to be too abstract and cold;
we lose the feeling of the mysterious which all life should suggest. In
our inhibiting conventionality we run the risk of false simplification.
Therefore, at the risk of a little repetition, we devote the rest of this dis-
cussion to what might be called "glimpses of life" — the contrast between
the living creature and a crystal, the quality of vital insurgence, the fact
of organic beauty.

CRYSTALS AND ORGANISMS. — When Linnaeus wrote his famous, yet now
partly outworn, aphorism, "Stones grow; Plants grow and live; Ani-
mals grow and live and feel," he must have been thinking of crystals.
For ordinary stones do not grow — except smaller; whereas crystals afford
beautiful illustrations of increase in size. Suppose, says Sir William Bragg
in his luminous lectures "Concerning the Nature of Things" (1925),
the crystallographer wishes to get a fine big crystal of common salt, he
suspends a minute, well-formed crystal in a solution of brine at a
concentration just ready to form a salt precipitate. That is step one. He
also makes sure of a certain temperature, which he knows from previous
experience to be suitable to tempt the atoms of sodium and chlorine to give
up their freedom "when they meet an assemblage of atoms already in per-
fect array — that is to say when they come across a suspended crystal."
Sometimes the solution is kept in gentle movement so that various parts

292 THE RIDDLE OF LIFE

of it get a chance of meeting the nucleus, which, so to speak, tempts them
to settle down — freezing into architecture. Into the physics of this we
need not here enter; our point is simply that in a suitable environment,
with time and quiet, a crystal-unit "grows." By accretion it becomes a
handsome large crystal. Onto its faces other crystal-units are added, and
on the new faces more again, until there is formed — an edifice. . . .

The crystal increases in size in an orderly way; how does this differ
from the growth of an animal or a plant? Is there a real resemblance, or
is it a misleading analogy? The first answer is that a crystal increases in
size at the expense of material, usually a solution, that is chemically the
same as itself; whereas animals and plants feed on substances different
from their own living matter — often very different. This is sound com-
monsense, and yet the edge is taken off it a little by two facts, first that
it is possible to feed an amoeba on amoebae, or a tadpole on tadpoles, or q
rat on rats; and, secondly, it is possible to increase the size of a crystal
when it is placed in a solution of a chemically different substance, which
has, however, the same form of crystallisation.

Then one might lay emphasis on the fact that the increase in the size
and weight of a crystal is by accretion from without, whereas organisms
grow by taking in raw materials, altering these, and building from
within. . . .

But there is another, more general, way of looking at the difference
between crystal increase and organic growth: the one is passive and the
other is active. It is not so much that the crystal grows, as that it is added
to by other crystal units — usually, moreover, in saturated solution. But an
organism actively takes in its food, actively changes and distributes it,
and actively builds with it.

But some authorities who press the analogy between crystals and crea-
tures bring forward another supposed resemblance. If a crystal is broken
there is a neat mending, provided there is the proper environment. There
is more rapid accretion at the broken surface than elsewhere; the repair is
often in proportion. This is very suggestive of the way in which an animal
or a plant replaces a lost part or repairs an injury. If a crystal be broken
into two, each half may form a perfect whole. If a Planarian worm or a
Hydra be cut across, each half usually "regenerates" an entire animal.
But the crystal's "regeneration" is passive, from without, and homo-
geneous; that of the organism is active, from within, and heterogeneous.

Another supposed resemblance that has been emphasised is the power
of lying latent that may be seen in crystal and creature alike. The seed of a
plant may remain dry for a decennium, but sow it and it will germinate.
The egg or the half-developed embryo of an animal may lie unchanged

THE CHARACTERISTICS OF ORGANISMS 293

for many years, but give it the appropriate environment and it will resume
its activity. Entire animals like "vinegar-eels" may remain without hint of
life for many years; but it is only necessary to put them in their proper
surroundings to see them revive and multiply. Everyone knows how the
spores of microbes may lie low for a long time and be blown about by the
wind, but let one light on a suitable medium and it reasserts its power —
perhaps its virulence to our undoing.

Now it is a similar power of lying latent that enthusiasts claim for
crystals. Thus Dr. A. E. H. Tutton, one of the leading authorities, says:
The virility of a crystal is unchanged and permanent. He pictures very
vividly what may happen to a crystal of quartz detached by the weather-
ing of a piece of granite thousands of years ago. It may be "subsequently
knocked about the world as a rounded sand grain, blown over deserts by
the wind, its corners rounded off by rude contact with its fellows and
subjected to every variety of rough treatment." But if it happen in our own
day to "find itself in water containing in solution a small amount of the
material of which quartz is composed, silicon-dioxide, it will begin to
sprout and grow again." From a grain of sand in such conditions several
typical crystals of quartz may grow out in different directions. "This
marvellously everlasting power possessed by a crystal, of silent imper-
ceptible growth, is one of the strangest functions of solid matter, and one
of the fundamental facts of science which is rarely realised, compared with
many of the more obvious phenomena of nature."

But Dr. Tutton chose a very resistant crystal; what he says of the crystal
of quartz would not be so true of a crystal of common salt, just as what
we said of the vinegar thread worm woufd not hold for the earthworm.
When atoms are very firmly locked together in an intricate space-lattice
system we do not expect them to be changeful. It is not easy to induce a
diamond to change its state. But the persistence of some organisms through
years of latent life is much more remarkable, for they often become dry
and brittle, and thus pass out of the colloidal state which is characteristic
of living matter. Yet they do not die. As for the prolonged persistence
of some organisms when they are not in a latent state, the marvel there
is that they retain their intact integrity in spite of the ceaseless internal
bustle of metabolism. Plus fa change, plus c'est la meme chose.

It is certainly a noteworthy fact that many kinds of crystals, not larger
than bacteria, float about in the air as microbes do. And just as a microbe
may set up a far-reaching change when it lights on a suitable medium, so
a microscopic crystal landing in a solution which is in a properly receptive
condition may set up crystallisation. But the differences seem to us to be
greater than the resemblances; for the minute crystal is but a passive peg

294 THE RIDDLE OF LIFE

to which molecules attach themselves, while the microbe is an active agent
that attacks the medium and fills it with its progeny.

No one wishes to think of living creatures as if they had not antecedents
in the non-living world. Science is not partial to Melchizedeks. On the
other hand, we hold to the apartness and uniqueness of life. Dr. A. E. H.
Tutton begins his fine book on The Natural History of Crystals (London,
1924), by saying that no definition of life has yet been advanced that will
not apply equally well to crystals, but we have given reasons for not accept-
ing this statement. The living creature's growth, repair, and reproduction
are very different from those of crystals; life is an enduring activity,
persisting in spite of its metabolism; the organism enregisters its experience
and acts on its environment; it is a masterful, even creative, agency. The
crystal, especially the gem, is a new synthesis, compared with the disarray
of the dust; the organism is another and on a different line.

THE INSURGENCE OF LIFE. — It is difficult to find the fit word to de-
note the quality of irrepressibility and unconquerability which is char-
acteristic of many living creatures. There are some, no doubt, that
drift along, but it is much more characteristic to go against the stream.
Life sometimes strikes one as a tender plant, a flickering flame; and
who can forget that one of the Ephemerides or mayflies has an aerial
life of but a single hour! At other times, the impression we get is just
the opposite, for the living creature often shows itself tenacious, tough,
and dogged. In his admirable Introduction to the Study of Trees (Home
Univ. Library, 1927), Dr. Macgregor Skene of Bristol University men-
tions that three carefully measured stumps of the "big tree," Sequoia
gigantea, of California showed rings going back to 1,087, 1,122, and 1,305
years B.C. The actual record for the second tree was 2,996 years and for
the third 3,197, without allowing for some rings that have been lost in
the centre. A specimen of the dragon-tree on Teneriffe is supposed to be
6,000 years old, and a bald cypress near Oaxaca in Mexico, no feet high
with a circumference of 107 feet at breast height, is credited with over
6,000 years. As these giants are still standing, their longevity is inferred,
whereas that of the felled Sequoias is proved by the ring counts. But,
in any case, there is astounding tenacity of life, and, without going out
of Britain, we may find other impressive illustrations. For, as Dr. Skene
says, "it is quite certain that we have many oaks which have passed
their thousand years, and some which may be much older." Another
way of looking at the insurgence of life is to think of some of the extraor-
dinary haunts which many living creatures have sought out. Colonel
Meinertzhagen, speaking recently of the lofty Tibetan plateau, directed
attention to the herds of antelopes and kiangs (wild ponies) that seem to

THE CHARACTERISTICS OF ORGANISMS 295

be able to thrive on next to nothing! The explorer marked out with his
field-glass an area where he saw a small herd of kiangs feeding, and then
visited the spot. Measuring a space one hundred yards by ten, he gathered
up every scrap of vegetation, and the result was a quaint collection —
seventeen withered blades of coarse grass and seven small alpines — not
enough to feed a guinea-pig! Of course, the kiangs had been there before
him, but there was little but very frugal fare all around. Meinertzhagen,
to whom we owe much information on the altitude of bird flight, saw a
flock of swifts at 18,800 feet. At 19,950 feet he shot a raven which showed
undue inquisitiveness as to his movements; at 21,059 feet> t'ie highest
point reached, he found a family of wall-creepers — dainty little refugees
of the mountains. Facts like these must be taken into consideration in
our total conception of life, for they are surely as essential to the picture
as the semi-permeability of the cell-membrane, or any other fundamental
fact of life-structure. No doubt hunger is a sharp spur; the impelling
power of the struggle for existence cannot be gainsaid; but we cannot get
away from the impression that we must also allow for something
analogous to the spirit of adventure. At all events, the facts show that
while the environment selects organisms, often winnowing very roughly,
there are other cases where organisms select their environment, and often
adventurously. There is a quality of tentativeness in many organisms,
that look out not merely for niches of opportunity into which to slink,
but for new kingdoms to conquer.

THE FACT OF BEAUTY. — No one who studies Animate Nature can get
past the fact of Beauty. It is as real in its own way as the force of
gravity. It used to be spoken of as though it were a quality of the exotic
— of the Orchid and the Bird of Paradise — now we feel it most at our
doors. St. Peter's lesson has been learned, and we find naught common
on the earth. As one of our own poets has said: Beauty crowds us all our
life. We maintain that all living things are beautiful; save those which
do not live a free life, those that are diseased or parasitised, those that
are half-made, and those which bear the the marks of man's meddling
fingers — monstrosities, for instance, which are naturally non-viable,
but live a charmed life under human protection. With these excep-
tions all living creatures are beautiful, especially when we see them
in their natural surroundings. To those who maintain that Animate
Nature is spotted with ugliness, we would reply that they are allowing
themselves to be preoccupied with the quite exceptional cases to which
we have referred, or that they are unable to attain the detachment
required in order to appreciate the esthetic points of, say, a snake or any
other creature against which there is a strong racial or personal prejudice.

296 THE RIDDLE OF LIFE

To call a jellyfish anything but beautiful is either a confusion of thought
or a submission to some unpleasant association, such as being severely
stung when bathing. That there are many quaint, whimsical, grotesque
creatures must be granted, to which conventionally minded zoologists
who should have known better have given names like Moloch horridus,
but we have never found any dubiety in the enthusiasm with which artists
have greeted these delightfully grotesque animals; and the makers of
beauty surely form the court of appeal for all such cases.

When we say that all free-living, fully formed, healthy living creatures
are beautiful, we mean that they excite in the spectator the characteristic
kind of emotion which is called esthetic. The thing of beauty is a joy for
ever. The esthetic emotion is distinctive; it brings no satiety; it is annexed
to particular qualities of shape, colour, and movement; it grows as we
share it with others; it grips us as organisms, body and soul, and remains
with us incarnate. Why should the quality of exciting this distinctive emo-
tion be pervasive throughout the world of organisms, as compelling in new
creatures which the human eye never saw before as in the familiar
favourites with which our race has grown up? It is possible that some
light is thrown on this question when we analyse the esthetic delight which
every normally constituted man feels when he watches the Shetland ponies
racing in the field, the kingfisher darting up the stream like an arrow made
of a piece of rainbow, the mayflies rising in a living cloud from a quiet
stretch of the river, or the sea-anemones nestling like flowers in the niches
of the seashore rocks. The forms, the colours, the movements, set up
agreeable rhythmic processes in our eyes, agreeable rhythmic messages
pass to our brain, and the good news — the pleasedness — is echoed through-
out the body, in the pulse, for instance, and in the beating of the heart, as
Wordsworth so well knew. The esthetic emotion is certainly associated
with a pleasing bodily resonance; in other words, it has its physiological
side. The second factor in our esthetic delight is perceptual. The "form"
of what we contemplate is significant for us and satisfies our feeling. The
more meaning is suffused into the material, the more our sense of beauty
is enhanced. The lines and patterns and colours of living creatures go to
make up a "form" which almost never disappoints. . . . We suggest for
consideration the general conclusion that all free-living, full-grown,
wholesome organisms have the emotion-exciting quality of beauty. And
is not our humanly sympathetic appreciation of this protean beauty of
the world inherent and persistent in us as also part of the same world of
life, and evolved far enough to realise it more fully, communicate it tG
each other more clearly?

1931

Leeuwenhoek

FIRST OF THE MICROBE HUNTERS
PAUL DE KRUIF

From Microbe Hunters

HUNDRED AND FIFTY YEARS AGO AN OBSCURE
man named Leeuwenhoek looked for the first time into a mysterious
new world peopled with a thousand different kinds of tiny beings, some
ferocious and deadly, others friendly and useful, many of them more im-
portant to mankind than any continent or archipelago.

Leeuwenhoek, unsung and scarce remembered, is now almost as un-
known as his strange little animals and plants were at the time he dis-
covered them. This is the story of Leeuwenhoek, the first of the microbe
hunters. . . . Take yourself back to Leeuwenhoek's day, two hundred and
fifty years ago, and imagine yourself just through high school, getting
ready to choose a career, wanting to know —

You have lately recovered from an attack of mumps, you ask your father
what is the cause of mumps, and he tells you a mumpish evil spirit has got
into you. His theory may not impress you much, but you decide to make
believe you believe him and not to wonder any more about what is mumps
— because if you publicly don't believe him you are in for a beating and
may even be turned out of the house. Your father is Authority.

That was the world about three hundred years ago, when Leeuwenhoek
was born. It had hardly begun to shake itself free from superstitions, it was
barely beginning to blush for its ignorance. It was a world where science
(which only means trying to find truth by careful observation and clear
thinking) was just learning to toddle on vague and wobbly legs. It was a
world where Servetus was burned to death for daring to cut up and
examine the body of a dead man, where Galileo was shut up for life for
daring to prove that the earth moved around the sun.

297

298 THE RIDDLE OF LIFE

Antony Leeuwenhoek was born in 1632 amid the blue windmills and
low streets and high canals of Delft, in Holland. His family were burghers
of an intensely respectable kind and I say intensely respectable because
they were basket-makers and brewers, and brewers are respectable and
highly honored in Holland. Leeuwenhoek's father died early and his
mother sent him to school to learn to be a government official, but he left
school at sixteen to be an apprentice in a dry-goods store in Amsterdam.
That was his university. . . .

At the age of twenty-one he left the dry-goods store, went back to Delft,
married, set up a dry-goods store of his own there. For twenty years after
that very little is known about him, except that he had two wives (in suc-
cession) and several children most of whom died, but there is no doubt
that during this time he was appointed janitor of the city hall of Delft, and
that he developed a most idiotic love for grinding lenses. He had heard
that if you very carefully ground very little lenses out of clear glass, you
would see things look much bigger than they appeared to the naked eye. . . .

It would be great fun to look through a lens and see things bigger than
your naked eye showed them to you! But buy lenses? Not Leeuwenhoek!
There never was a more suspicious man. Buy lenses? He would make
them himself! During these twenty years of his obscurity he went to spec-
tacle-makers and got the rudiments of lens-grinding. He visited alchemists
and apothecaries and put his nose into their secret ways of getting metals
from ores, he began fumblingly to learn the craft of the gold- and silver-
smiths. He was a most pernickety man and was not satisfied with grinding
lenses as good as those of the best lens-grinder in Holland, they had to be
better than the best, and then he still fussed over them for long hours.
Next he mounted these lenses in little oblongs of copper or silver or gold,
which he had extracted himself, over hot fires, among strange smells and
fumes. . . .

Of course his neighbors thought he was a bit cracked but Leeuwenhoek
went on burning and blistering his hands. Working forgetful of his
family and regardless of his friends, he bent solitary to subtle tasks in still
nights. The good neighbors sniggered, while that man found a way to
make a tiny lens, less than one-eighth of an inch across, so symmetrical, so
perfect, that it showed little things to him with a fantastic clear enormous-
ness. . . .

Now this self-satisfied dry-goods dealer began to turn his lenses onto
everything he could get hold of. He looked through them at the muscle
fibers of a whale and the scales of his own skin. He went to the butcher
shop and begged or bought ox-eyes and was amazed at how prettily the
crystalline lens of the eye of the ox is put together. He peered for hours ar

LEEUWENHOEK: FIRST OF THE MICROBE HUNTERS 299

the build of the hairs of a sheep, of a beaver, of an elk, that were trans-
formed from their fineness into great rough logs under his bit of glass. He
delicately dissected the head of a fly; he stuck its brain on the fine needle
of his microscope — how he admired the clear details of the marvelous big
brain of that fly! He examined the cross-sections of the wood of a dozen
different trees and squinted at the seeds of plants. He grunted "Impos-
sible!" when he first spied the outlandish large perfection of the sting of a
flea and the legs of a louse. That man Leeuwenhoek was like a puppy who
sniffs — with a totally impolite disregard of discrimination — at every object
of the world around him!

ii

But at this time, in the middle of the seventeenth century, great things
were astir in the world. Here and there in France and England and Italy
rare men were thumbing their noses at almost everything that passed for
knowledge. "We will no longer take Aristotle's say-so, nor the Pope's
say-so," said these rebels. "We will trust only the perpetually repeated
observations of our own eyes and the careful weighings of our scales; we
will listen to the answers experiments give us and no .other answers!" So
in England a few of these revolutionists started a society called The Invisi-
ble College, it had to be invisible because that man Cromwell might have
hung them for plotters and heretics if he had heard of the strange ques-
tions they were trying to settle.

. . . Remember that one of the members of this college was Robert Boyle,
founder of the science of chemistry, and another was Isaac Newton. Such
was the Invisible College, and presently, when Charles II came to the
throne, it rose from its depths as a sort of blind-pig scientific society to the
dignity of the name of the Royal Society of England. And they were
Antony Leeuwenhoek's first audience! There was one man in Delft who
did not laugh at Antony Leeuwenhoek, and that was Regnier de Graaf,
whom the Lords and Gentlemen of the Royal Society had made a corre-
sponding member because he had written them of interesting things he
had found in the human ovary. Already Leeuwenhoek was rather surly and
suspected everybody, but he let de Graaf peep through those magic eyes
of his, those little lenses whose equal did not exist in Europe or England
or the whole world for that matter. What de Graaf saw through those
microscopes made him ashamed of his own fame and he hurried to write
to the Royal Society:

"Get Antony Leeuwenhoek to write you telling of his discoveries."

And Leeuwenhoek answered the request of the Royal Society with all
the confidence of an ignorant man who fails to realize the profouncj

300 THE RIDDLE OF LIFE

wisdom of the philosophers he addresses. It was a long letter, it rambled
over every subject under the sun, it was written with a comical artlessness
in the conversational Dutch that was the only language he knew. The title
of that letter was: "A Specimen of some Observations made by a Micro-
scope contrived by Mr. Leeuwenhoek, concerning Mould upon the Skin,
Flesh, etc.; the Sting of a Bee, etc." The Royal Society was amazed, the
sophisticated and learned gentlemen were amused — but principally the
Royal Society was astounded by the marvelous things Leeuwenhoek told
them he could see through his new lenses. The Secretary of the Royal
Society thanked Leeuwenhoek and told him he hoped his first communica-
tion would be followed by others. It was, by hundreds of others over a
period of fifty years. They were talkative letters full of salty remarks about
his ignorant neighbors, of exposures of charlatans and of skilled explodings
of superstitions, of chatter about his personal health — but sandwiched be-
tween paragraphs and pages of this homely stuff, in almost every letter,
those Lords and Gentlemen of the Royal Society had the honor of reading
immortal and gloriously accurate descriptions of the discoveries made by
the magic eye of that janitor and shopkeeper. What discoveries!

. . . When Leeuwenhoek was born there were no microscopes but only
crude hand-lenses that would hardly make a ten-cent piece look as large as
a quarter. Through these — without his incessant grinding of his own mar-
velous lenses — that Dutchman might have looked till he grew old without
discovering any creature smaller than a cheese-mite. You have read that
he made better and better lenses with the fanatical persistence of a lunatic;
that he examined everything, the most intimate things and the most
shocking things, with the silly curiosity of a puppy. Yes, and all this
squinting at bee-stings and mustache hairs and what-not were needful to
prepare him for that sudden day when he looked through his toy of a gold-
mounted lens at a fraction of a small drop of clear rain water to discover —

What he saw that day starts this history. Leeuwenhoek was a maniac ob-
server, and who but such a strange man would have thought to turn his
lens on clear, pure water, just come down from the sky? What could there
be in water but just — water? You can imagine his daughter Maria — she
was nineteen and she took such care of her slightly insane father! — watch-
ing him take a little tube of glass, heat it red-hot in a flame, draw it out to
the thinnest of a hair. . . .

He squints through his lens. He mutters guttural words under his
breath. . . .

Then suddenly the excited voice of Leeuwenhoek: "Come here! Hurry!
There are little animals in this rain water. . . . They swim! They play

LEEUWENHOEK: FIRST OF THE MICROBE HUNTERS 301

around! They are a thousand times smaller than any creatures we can see
with our eyes alone. . . . Look! See what I have discovered!"

Leeuwenhoek's day of days had come. . . . This janitor of Delft had
stolen upon and peeped into a fantastic sub-visible world of little things,
creatures that had lived, had bred, had battled, had died, completely
hidden from and unknown to all men from the beginning of time. Beasts
these were of a kind that ravaged and annihilated whole races of men ten
millions times larger than they were themselves. Beings these were, more
terrible than fire-spitting dragons or hydra-headed monsters. They were
silent assassins that murdered babes in warm cradles and kings in sheltered
places. It was this invisible, insignificant, but implacable — and sometimes
friendly — world that Leeuwenhoek had looked into for the first time of all
men of all countries.

This was Leeuwenhoek's day of days. . . .

in

. . . How marvelous it would be to step into that simple Dutchman's
shoes, to be inside his brain and body, to feel his excitement — it is almost
nausea! — at his first peep at those cavorting "wretched beasties."

That was what he called them, and this Leeuwenhoek was an unsure
man. Those animals were too tremendously small to be true, they were
too strange to be true. So he looked again, till his hands were cramped
with holding his microscope and his eyes full of that smarting water that
comes from too-long looking. But he was right! Here they were again,
not one kind of little creature, but here was another, larger than the first,
"moving about very nimbly because they were furnished with divers in-
credibly thin feet." Wait! Here is a third kind — and a fourth, so tiny I
can't make out his shape. But he is alive! He goes about, dashing over
great distances in this world of his water-drop in the little tube. . . . What
nimble creatures!

"They stop, they stand still as 'twere upon a point, and then turn them-
selves round with that swiftness, as we see a top turn round, the circum-
ference they make being no bigger than that of a fine grain of sand." So
wrote Leeuwenhoek. . . .

But where did these outlandish little inhabitants of the rainwater come
from? Had they come down from the sky? Had they crawled invisibly
over the side of the pot from the ground? Or had they been created out of
nothing by a God full of whi